2х^2+10х-8=х^2+8х-5
2х^2+10х-8-х^2-8х+5=0
х^2+2х-3=0
D=4+12=16
x1=(-2+4)/2=1
x2=-3
Y1=4
Y2=-20
Ответ(1;4)(-3;-20)
5x-3y=8 -1=7 y+2x=5 (5-2x=3y)
X^2 - 6x + 9 - (x^2 - 9) + 5x + 22 =
= x^2 - 6x + 9 - x^2 + 9 + 5x + 22 =
= - x + 18 + 22 = - x + 40
5(12-х)-11(4х-5)=9(9-5х)-26
60-5х-44х+55=81-45х-26
-5х-44х+45х=81-26-60-55
-4х=-60
х=15
2a/(2a+b)-4a²/(2a+b)²=(4a²+2ab-4a²)/(2a+b)²=2ab/(2a+b)²
2a/((2a-b)(2a+b)-1/(2a-b)=(2a-2a-b)/(2a-b)(2a+b)=-b/(2a-b)(2a+b)
2ab/(2a+b)² : -b/(2a-b)(2a+b)=-2ab/(2a+b)² *(2a-b)(2a+b)/b=(2ab-4a²)/(2a+b)
-2a(2a-b)*[-(2a+b)/2a(2a-b)=1