(х-2)2=-х
2х-4=-х
х-4=0
х=4
1) -2, 5×8+,2, 5×3х =20+ 7,5х
2) 0,2×18х+0, 2×14= 3,6х+2, 8
3) 20+7, 5х+3, 6х+2, 8 =22, 8+11, 1х
ответ: 22,8+11, 1х
1) 2х² <span>+ 5х - 7 = 0
D = 25 + 56 = 81
x</span>₁ =
<span>
x</span>₂ =
<span>
Два корня
2) 3х</span>² <span>- 7х - 8 = 0
</span>D = 49 + 96 = 145
<span>
x</span>₁ =
<span>
x</span>₂ =
<span>
Два корня
3) 4х</span>² <span>+ 4х + 1 = 0
D = 16 - 16 = 0
x</span>₁ =
<span>
Один корень
4) 9х</span>² - 6х + 2 = 0
D = 36 - 72 = -36
D < 0 (корней нет)