Question

Completing the square: x^2+2x-7=8x

Answer 1

Answer: x = 7, x = -1

Step-by-step explanation: Move the term to the left side

x^2 + 2x - 7 = 8x

x^2 + 2x - 7 - 8x = 0

Combine like terms

x^2 + 2x - 7 - 8x = 0

x^2 - 6x - 7 = 0

x^2 - 6x - 7 = 0

a = 1

b = -6

c = -7

x = -(-6) + (-6)^2 - 4 x 1(-7)/ 2 x 1

Evaulate the Exponent

Multiply the numbers

Add the numbers

Evaluate the square root

Multiply the numbers x = 6 ± 8/2

To solve for the unknown variable, separate into two equations: one with a plus and the other with a minus.

x = 6 + 8/2

x = 6 - 8/2

Rearrange and isolate the variable to find each solution

x = 7

x = -1