Given a / x + 1 + B / x + 1 = x-3 / (x + 1) (x-1), find the value of a and B

Given a / x + 1 + B / x + 1 = x-3 / (x + 1) (x-1), find the value of a and B

On the right side = [a (x + 1) + B (x-3)] / (x-3) (x + 1) = [(a + b) x + (a-3b)] / (x-3) (x + 1) = (3x-5) / (x-3) (x + 1) = on the left side: (a + b) x + (a-3b) = 3x-5, corresponding to the same coefficients, there are: a + B = 3 and a-3b = - 5

What is the square of (2a-b) - 4 (a-b) multiplied by (a + 2b)?

Original formula = (2a-b) ^ 2-4 (a ^ 2 + ab-2b ^ 2)
=4a^2-4ab+b^2-4a^2-4ab+8b^2
=10b^2-8ab

Calculation: 3 times the square of a - a times the square of (3 times a-5 times b) - B times (2a-b) equals