7) 2/x+4 +1=3/x^2+8x+16 ,x не равен -4
2/x+4 +1= 3/x^2+8x+16=0
2/x+4 +1 -3/(x+4)^2=0
2(x+4)+(x+4)^2 -3/(x+4)^2 =0
2x+8+(x+4)^2-3/(x+4)^2 =0
2x+5+x^2+8x+16/(x+4)^2 =0
10x+21+x^2=0
x^2+10x+21=0
x^2+7x+3x+21=0
x*(x+7)+3(x+7)=0
(x+7)*(x+3)=0
x+7=0 и x+3=0
x=-7 и x=-3 , x не равен -4
x1=-7 , x2=-3
