Question

а)у^2+7у-8=0
b) kx^2+8x+k=0 k=?
Помогите ​

Answer 1

Ответ:

а) D=49-4×(-8)×1=81

y1=(-7+9)/2×1 = 2/2 = 1

y2 = (-7-9)/2×1 = -16/2= -8

b) D=64-4×k×k=64-4k2

$d = 64 - 4 \times k \times k = 64 - 4 {k}^{2}$

$64 - 4 {k }^{2} = 0 \\ 4 {k}^{2} = 64 \\ {k}^{2} = 64 \div 4 \\ {k}^{2} = 16 \\ k1 = - 4 \\ k2 = 4$