1)(a-1)(a+1)/(1-a)=-(a+1);
2)=(m-n)/(m-n)^2=1/(m-n);
3)=(x+1)^2/(x-1)(x+1)=(x+1)/(x-1);
4)=(a-1)(a+1)/(a-1)^2=(a+1)/(a-1)
<span>а) 5х² - 3= х² - 3
</span> 5х² - х²-<span>3+3= 0
4х</span>²=0
х=0
<span>б) х² + 15х = 8х
х</span>²+15х-8х=0
х²+7х=0
х*(х+7)=0
х₁=0 х+7=0
х₂=-7
в) <span>х (х-2) = -х²
х</span>²-2х+х²=0
2х²-2х=0
2х*(х-1)=0
2х=0 ⇒ х₁=0
х-1=0 ⇒х₂=1
(cos²40° -sin²40°) /(cos40° +sin40°) = (cos40° -sin40°)(cos40° +sin40°) /(cos40° +sin40°)=
cos40° - sin40° =sin50° - sin40° =2sin(50° - 40)/2 *cos(50°+ 40)/2 =2sin5° *cos45° =
=√2 * sin5° .