1) (7b^2+2a-7b^2)/b = 2a/b = 2*9/12 = 18/12 = 3/2 = 1,5
2) (xy+y^2)/(15x)*(3x)/(x+y) = y(x+y)/5*1/(x+y) = y/5 = 7,5/5 = 1,5
3) 10x/(2x-3) - 5x(2x-3)/(2x-3) = (10x-10x^2+15x)/(2x-3) = 5x(-2x+5)/(2x-3) =
= 2,5(-1+5)/(1-3) = 2,5*4/(-2) = - 5
4) 64(b^2+2b+1)/b : (4+4b)/b = 64(b+1)^2 / (4(b+1)) = 16(b+1) =
= 16(1-15/16) = 16*1/16 = 1
5) a(a^2-25)*(a-5-a-5)/(a^2-25) = a*(-10) = - 39*(-10) = 390
Решение полное смотри на фотках
1) (7b^2+2a-7b^2)/b = 2a/b = 2*9/12 = 18/12 = 3/2 = 1,5
2) (xy+y^2)/(15x)*(3x)/(x+y) = y(x+y)/5*1/(x+y) = y/5 = 7,5/5 = 1,5
3) 10x/(2x-3) - 5x(2x-3)/(2x-3) = (10x-10x^2+15x)/(2x-3) = 5x(-2x+5)/(2x-3) =
= 2,5(-1+5)/(1-3) = 2,5*4/(-2) = - 5
4) 64(b^2+2b+1)/b : (4+4b)/b = 64(b+1)^2 / (4(b+1)) = 16(b+1) =
= 16(1-15/16) = 16*1/16 = 1
5) a(a^2-25)*(a-5-a-5)/(a^2-25) = a*(-10) = - 39*(-10) = 390
Решение полное смотри на фотках