(а+3)(а-7)=а^2 - 7a +3a - 21 = а^2 - 4a - 21
(3m-2)(3m-2)-2(m-2)(m-3)+(2m-1)(2m+1)
9m²-6m-6m-4-2(m²-3m-2m+6)+(4m²+2m-2m-1)
<u>9m²</u>-6m-6m-4<u>-2m²</u>+10m-12+<u>4m²</u>+2m-2m-1
11m²-2m-17
D=b²-4ac=2²·-4·11·(-17)=32912
x1=-17
x2=34
Одз: 5-х > 0; х < 5.
log(3)[5-х] = log(3)3^5
5-x = 243;
x = 5-243;
x = -238.
ответ : х = -238 ( корень входит в одз).
(x+2)(x²-2x+4)-x(x-3)(x+3)-42=(x³-2x²+4x+2x²-4x+8)-x(x²-9)-42=x³+8-x³+9x-42=9x+8-42=9x-34
(x-3)(x²+3x+9)-x(x²-16)+21=(x³+3x²+9x-3x²-9x-27)-x³+16x+21=x³-27-x³+16x+21=16x-27+21=16x-6