Question

Срочно плиз решать задачу

Answer 1

Ответ:

1)28а+21b-30a-42b= -2a-21b= -2*(2)-21*(3)= -70

2)a(2b + 1) - b(2a - 1) = 2ab + a - 2ab + b = = a + b = = 10 + (-5) = 10 - 5 = 5.

3)3ab(4a*2-b*2)+4ab(b*2-3a*2)=3ab(8a-2b)+4ab(2b-6a)=24a²b-6ab²+8ab²-

24a²b=-6ab²+8ab²=2ab²=2*10*(-5)²=20*25=500

4)4a^2 (5a-3b) - 5a^2 (4a+b) = 20a^3-12a^2b-20a^3--5a^2b = - 17a^2b = - 17 * (-2) ^2 * (-3) = - 17*4 * (-3) = 204