(4a-b)²=(4a)²-2*4a*b+b²=16a²-8ab+b²
(4a-b)³=(4a)³-3*(4a)²*b+3*4a*b²-b³=64a³-48a²b+12ab²-b³
(4a+b)³=(4a)³+3*(4a)²*b+3*4a*b²+b³=64a³+48a²b+12ab²+b³
(2 - x)² - (3x + 5)² = (2 - x + 3x + 5)(2 - x - 3x - 5) =
=(2x + 7)(-4x - 3) = -(2x + 7)(4x + 3)
А)5х-8,5=0; 5х = 8,5; х= 8,5 : 5; х=1,7 б)8х-7,5=6х+1,5; 8х-6х=1,5+7,5; 2х=9; х=9:2; х=4,5; в)4х-(9х-6)=46; 4х-9х+6=46; 4х-9х=46-6; -5х=40; х=40:(-5); х= - 8. г)(х-2,5)(5+х)=0; 5х + х - 12, 5 - 2,5=0; 5х+х^2 - 2,5х-12,5=0; х^2 +2,5х -12,5=0; Д:b^2-4ас=6,25-4*1*(-12,5)=6,25+50=56,25; х1=(-2,5+7,5)/2 =5/2=2,5; х2=(-2,5-7,5)/2=-10/2=-5; д)7х-(х+3)=3(2х-1); 7х-х-3=6х-3; 7х-х-6х=3-3; 0=0