4х-7х+2=17
-3х=17-2
-3х=15 |:(-3)
х=-5
ответ:х=-5
2)a²-16+b²-2ab= a²-2ab+b²-16=(a-b)²-4²=(a-b-2)(a-b+2)
1)а²+b²-2ab-c²=(a-b)²-c²=(a-b-c)(a-b+c)
1. х(4х+20)=0
х=0. 4х+20=0
4х=-20
х=-5
2. 4y/(y^2-x^2)-2/(y-x)= 4y/(y+x)(y-x)- 2*(y+x)/(y-x)= 4y-2y-2x/(y+x)(y-x)=2y-2x/(y+x)(y-x)=2(y-x )/(y+x)(y-x)=2/(y+x)
Ответ:........................