8m+2-(5-7m)-4m =8m+2-5+7m-4m= (8+7-4)m+(2-5)=11m-3
при m= -2
11*(-2)-3=-22-3= -25
1)3/х+3 + 3/х2-3х + 2х/9-х2=3/х+3 + 3/х(х-3) + 2х/(3-х)(3+х)=3•(х(х-3) + 3•(х+3) -2х•х/х(х+3)(х-3)= 3х2-9х+3х+9-2х2/х(х-3)(х+3)=х2-6х+9/х(х-3)(х+3)=(х-3)2/х(х-3)(х+3)=х-3/х2+3х
3)а^2-b/a-a=0,04+25-0,2=24,84
8х-1-2х-1
=------------=
3х-1
6х-2
=-------=2(3х-1)/(3х-1)=2
3х-1
X^2-2x-63>0
x1,2 = (2+-16)/2= -7;9
x<=-7
x>=9
-x^2 -5x +36>=0
x^2+5x-36<=0
По теореме виета корни:
x=-9
x=4
4>=x>=-9