Question

Help please, find the solution(s) for x In the equation below.

x2 + 7x = 8
OA. x = -1; x = 8
ОВ. x = 1; x = 8
OC. x = 1; x = 8
OD. x = -1; x = -8

Answer 1

The correct answer is C, x = 1; x = -8

Explanation:

• Quadratic formula:
  `x=(-b\±√(b^2-4ac))/(2a)`

`x^2+7x=8`

`x^2+7x-8=0` <== a = 1, b = 7, c = -8

`x=(-b\±√(b^2-4ac))/(2a) \\\\x=(-7\±√(7^2-4*1*-8))/(2*1) \\\\x=(-7\±√(7^2-4*-8))/(2) \\\\x=(-7\±√(49+32))/(2) \\\\x=(-7\±√(81))/(2) \\\\x=(-7\±9)/(2) \\\\x=(-7+9)/(2)\ \ and\ \ x=(-7-9)/(2) \\\\x=(2)/(2)\ \ and\ \ x=(-16)/(2) \\\\x=1\ \ and\ \ x-8\\\\x=1,\ x-8`

Hope this helps!