Question

(2а-5)^2+(1-3а)(3-2а)-7а^2

Answer 1

4a²-20a+25+3-2a-9a+6a²-7a²= 3a²-31a+28

Answer 2

Let's simplify the expression step by step:

(2a-5)^2 = (2a-5)(2a-5) = 4a^2 - 10a - 10a + 25 = 4a^2 - 20a + 25

(1-3a)(3-2a) = 1(3-2a) - 3a(3-2a) = 3 - 2a - 9a + 6a^2 = 6a^2 - 11a + 3

Now, let's substitute these simplified expressions into the original expression:

(2a-5)^2 + (1-3a)(3-2a) - 7a^2 = (4a^2 - 20a + 25) + (6a^2 - 11a + 3) - 7a^2 = 4a^2 - 20a + 25 + 6a^2 - 11a + 3 - 7a^2 = (4a^2 + 6a^2 - 7a^2) + (-20a - 11a) + (25 + 3) = 3a^2 - 31a + 28

So, the simplified form of the expression (2a-5)^2 + (1-3a)(3-2a) - 7a^2 is 3a^2 - 31a + 28.