10(х-9)=7
10х-90=7
10х=97
х=9,7
36x^3-84x^2+49x=0
x(36x^2-84x+49)=0
x=0 или 36x^2-84x+49=0
Д=84^2-4*36*49=0
x1/2=84+-0/36*2=1 1/6
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2x(3x-4)-(x-6)(x-1)=6x²-8x-(x-6)(x-1)=6x²-8x-x²+7x-6=5x²-x-6
(2х + 3)(12у + 4) = 2х * 12у + 4 * 2х + 3 * 12у + 3 * 4 = 24ху + 8х + 36у + 12