Evaluate (−7) + 4 − (−2).
- 5
- 1
- −5
- −1 Correct answer.
Explanation
Work left to right: (−7) + 4 = −3, then −3 − (−2) = −3 + 2 = −1. Subtracting a negative number is the same as adding its opposite.
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Work left to right: (−7) + 4 = −3, then −3 − (−2) = −3 + 2 = −1. Subtracting a negative number is the same as adding its opposite.
(−3) × (−4) = 12, and 2 × 5 = 10, so 12 − 10 = 2. The product of two negatives is positive.
(−2)² = 4, so 4 × (−3) = −12. A negative base squared is positive; multiplying that by a negative gives a negative product.
√72 = √(36·2) = 6√2 and √50 = √(25·2) = 5√2, so 6√2 − 5√2 = √2. Simplify each radical before combining like terms.
Combine under one radical: √18 × √2 = √(18 × 2) = √36 = 6. Multiplication of square roots merges the radicands.
Multiply numerator and denominator by √3: 6/√3 = (6√3)/3 = 2√3. Rationalizing removes the radical from the denominator.
This is a difference-of-squares product: (√3)² − (√2)² = 3 − 2 = 1. The cross terms cancel in (a+b)(a−b) = a² − b².
(−2)³ = −8, so −8 × (1/2) = −4. An odd power keeps the negative sign.
0.375 = 375/1000; dividing numerator and denominator by 125 gives 3/8. Reduce by the greatest common divisor.
This is a difference of squares: (x + 4)(x − 4) = x² − 16. The middle terms cancel because the constants are opposites.
FOIL: 2x·x = 2x², 2x·(−2) = −4x, 3·x = 3x, 3·(−2) = −6. The middle terms combine to −4x + 3x = −x, giving 2x² − x − 6.
We need two numbers whose product is −14 and sum is −5: −7 and +2. So x² − 5x − 14 = (x − 7)(x + 2).
a² − 2ab + b² = (a − b)² = (2 − (−3))² = 5² = 25. Recognizing the perfect-square form shortens the arithmetic.
Add 5 to both sides: 2x = 12, then divide by 2: x = 6. Isolate the variable with inverse operations.
Divide both sides by 3 first: x + 1 = 4, so x = 3. You may also distribute first; both orders agree.
Subtract 3: x/2 = 4, then multiply by 2: x = 8. Undo the addition before clearing the denominator.
Distribute the minus: 2x − x − 4 = −3x + 8, so x − 4 = −3x + 8. Add 3x and add 4: 4x = 12, x = 3.
Subtract 2x and add 3: 3x = 12, so x = 4. Collect the variable terms on one side and constants on the other.
Add 7 to both sides: x < 10. Inequalities with addition behave like equations; no sign flip is needed.
Divide by 2: x − 3 ≥ 2, then add 3: x ≥ 5. Splitting the division first keeps the arithmetic clean.
Add the two equations: 2x = 14, so x = 7. Substitute back: 7 + y = 10, so y = 3. The elimination method removes y when the equations are summed.
From x − y = 1, x = y + 1. Substitute: 2(y + 1) + 3y = 12, so 5y + 2 = 12, y = 2, and x = 3. Substitution turns a system into one equation in one variable.
Multiply the first by 3 (9x + 6y = 48) and the second by 2 (4x + 6y = 28); subtract: 5x = 20, x = 4, then 2(4) + 3y = 14 gives y = 2.
Factor: (x − 5)(x + 2) = 0, so x = 5 or x = −2. The pair −5 and 2 has product −10 and sum −3.
Factor out x: x(x + 5) = 0, so x = 0 or x = −5. A common-factor quadratic always has 0 as one root.
When the coefficient of x² is not 1, use the quadratic formula x = (−b ± √(b² − 4ac)) / (2a). With a = 2, b = −7, c = 3: x = (7 ± √(49 − 24)) / 4 = (7 ± 5) / 4, giving x = 12/4 = 3 and x = 2/4 = 1/2. Substituting either value back into the original equation confirms both roots.
Using x = (−b ± √(b² − 4ac))/(2a) with a = 1, b = −4, c = 1: x = (4 ± √(16 − 4))/2 = (4 ± √12)/2 = (4 ± 2√3)/2 = 2 ± √3.
Let the integers be n and n + 2. Then n + (n + 2) = 26, so 2n = 24 and n = 12. The smaller even integer is 12; the pair is 12 and 14.
Let the son's age be s; the father is 3s. In 12 years: 3s + 12 = 2(s + 12) = 2s + 24, so s = 12. The son is 12 now; the father is 36.
Substitute: 15 = k·5, so k = 3. The constant of proportionality is the ratio y/x for any point on the line through the origin.
Substitute: 6 = k/2, so k = 12. For inverse proportion the product xy is constant.
Substitute x = 8: 8y = 24, so y = 3. Inverse proportion means the product is fixed; divide the constant by the given value.
Substitute: y = 2(−1) + 3 = −2 + 3 = 1. Take care with the sign of the substituted value.
Slope = (y₂ − y₁)/(x₂ − x₁) = (8 − 2)/(3 − 1) = 6/2 = 3. Rise over run between the two points.
In slope-intercept form y = mx + b, the constant b is the y-intercept. Here b = −4, so the line crosses the y-axis at (0, −4).
Slope-intercept form is y = mx + b. With m = −3 and b = 2, the equation is y = −3x + 2.
Rewrite as y = −2x + 5. The coefficient of x is the slope, so m = −2. Order the terms in slope-intercept form before reading off m.
Slope = (7 − 1)/(4 − 2) = 3. Using point-slope with (2, 1): y − 1 = 3(x − 2), so y = 3x − 6 + 1 = 3x − 5.
Parallel lines share the same slope, so m = 2. Using (3, 4): 4 = 2·3 + b, so b = −2 and the equation is y = 2x − 2.
Because the range of x includes 0, the graph passes through its lowest point, so the smallest value of y is 0 rather than the value at either endpoint. The largest value comes from whichever endpoint is farther from 0: x = 3 gives y = 9, while x = −1 gives only y = 1. The range is therefore 0 ≤ y ≤ 9.
The rate of change is the increase in y divided by the increase in x. Here y goes from 2 × 1² = 2 to 2 × 3² = 18, an increase of 16, while x increases by 2. So the rate of change is 16 ÷ 2 = 8. Unlike a straight line, this value changes depending on which interval of x you choose.
y = 2(3²) = 2·9 = 18. Square the input first, then multiply by the coefficient.
Factor: (x − 3)(x + 1) = 0, so x = 3 or x = −1. The pair −3 and +1 has product −3 and sum −2.
y(1) = 1 and y(4) = 10, so the rate of change is (10 − 1)/(4 − 1) = 9/3 = 3. For a linear function this equals the slope.
Substitute (2, 3): 3 = −2 + 5 = 3 ✓. The point's coordinates must satisfy the equation.
Substitute: 12 = a·2² = 4a, so a = 3. Divide by the squared input to isolate the coefficient.
Substitute (2, 10): 10 = 2m + 4, so 2m = 6 and m = 3. Isolate m by subtracting the intercept and dividing by x.
In y = ax², the sign of a decides which way the curve opens: a is negative here, so it opens downward. The size of a decides the width: the larger |a| is, the more steeply the curve rises or falls, so it looks narrower. Since |−2| = 2 is greater than 1, y = −2x² is narrower than y = x².
The point of intersection lies on both lines, so its coordinates satisfy both equations. Setting them equal: 2x − 1 = −x + 5, so 3x = 6 and x = 2. Substituting into either equation gives y = 2(2) − 1 = 3, so the lines meet at (2, 3). This is why solving a pair of simultaneous equations is the same as finding where two lines cross.
The angles of a triangle sum to 180°, so the third angle is 180 − 50 − 60 = 70°.