Question

-х в квадрате+7х+8=0

Answer 1

$-x {}^{2} + 7x + 8 = 0 \\ D = 7 {}^{2} - 4 \times 8 \times ( - 1) = 49 + 32 = 81 \\ x = \frac{ -7 - 9}{ - 2} \: \: x = \frac{ -7 + 9}{ - 2} \\ x = 8 \: \: \: \: \: \: x = - 1$

Ответ: -1;8

Answer 2

-x²+7x+8=0

x²-7x-8=0

D=49+32=81=9²

x=(7±9)/2

x1=8;x2=-1

Answer 3

To solve the quadratic equation -х^2 + 7х + 8 = 0, you can use the quadratic formula. The quadratic formula is given by:

x = (-b ± √(b^2 - 4ac)) / 2a

where a, b, and c are the coefficients of the quadratic equation ax^2 + bx + c = 0.

For the given equation, a = -1, b = 7, and c = 8. Now, let's plug these values into the quadratic formula to find the solutions for x:

x = (-(7) ± √(7^2 - 4(-1)(8))) / 2(-1)

x = (-7 ± √(49 + 32)) / -2

x = (-7 ± √81) / -2

Now, we have two solutions for x:

1. x = (-7 + √81) / -2 x = (-7 + 9) / -2 x = 2 / -2 x = -1

2. x = (-7 - √81) / -2 x = (-7 - 9) / -2 x = -16 / -2 x = 8

So, the solutions to the quadratic equation -х^2 + 7х + 8 = 0 are x = -1 and x = 8.