Вправи: 99

99. Виконайте додавання або віднімання дробів:

1) aa-2 – 3a+13a-6 = a\3a-2 – 3a+13(a-2) = 3a-(3a+1)3(a-2) = 3a-3a-13(a-2) = -13(a-2) = 13a-6 = 16-3a;

2) 18b2+3b – 6b = 18b(b+3) – 6\b+3b = 18-6(b+3)b(b+3) = 18-6b-17b(b+3) = -6bb(b+3( = –6b+3;

3) 2c+2 – c-1c2+ c = 2\c+1c+2 – c-2c(c+1) = 2c-(c-1)c(c+1) = 2c- c+1c(c+1) = c+1c(c+1) = 1c;

4) d-12d-8 + dd-4 = d-12(d-4) + d\2d-4 = d-1+2d3(d-4) = 3d-12d-8;

5) m+13m-15 – m-12m-10 = m+1\2 3(m-5) – m-1\3 2(m-5) = 2m+1-3(m-1)6(m-5) = 2m+2-3m+36(m-5) = -m+56(m-5( = -(m-5)6(m-5) = –16;

6) 3x-4yx2-2xy – 3y- xxy-2y2 = 3x-4y\yx(x-2y) – 3y- x\xy(x-2y) = y3x-4y- x(3y- x)xy(x-2y) = 3xy-4y2-3xy+ x2xy(x-2y) = x2-4y2xy(x-2y) = (x-2y)(x+2y)xy(x-2y) = x+2yxy.