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A day full of math games & activities. Find one near you.
A day full of math games & activities. Find one near you.
A day full of math games & activities. Find one near you.

Solve x2 − 8x − 20. x = 4, x = −5, x = −4, x = 5, x = 2, x = −10, x = −2, x = 10

The above given equation is a quadratic equation.

Answer: For x2 − 8x − 20, x = -2, 10

Substituting the x values in the given quadratic equation.

Explanation:

f(x) = x2 − 8x − 20

If x = 4, (4)2 - 8(4) -20 = 16 - 32 - 20 = -36

If x = -5, (-5)2 - 8(-5) -20 =  25 + 40 - 20 = 45

If x = -4, (-4)2 - 8(-4) -20 =  16 + 32 - 20 = 28

If x = 5, (5)2 - 8(5) -20 =  25 - 40 - 20 = -35

If x = 2, (2)2 - 8(2) -20 =  4 - 16 - 20 = -32

If x = -10, (-10)2 - 8(-10) -20 =  100 + 80 - 20 = 160

If x = -2, (-2)2 - 8(-2) -20 =  4 + 16 - 20 = 0

If x = 10, (10)2 - 8(10) -20 =  100 - 80 - 20 = 0

Therefore, after solving the x values, we get the solution as x = -2, 10

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