Answer:
See below in bold.
Explanation:
1. x^2 - 13x - 30
We need 2 numbers whose product is -30 and whose sum = -13.
They are -15 and + 2:
Answer is (x - 15)(x + 2).
2. 2x^2 + 4x - 126
First we can take 2 out to give:
2(x^2 + 2x - 63)
Now we need 2 numbers whose product is - 63 and sum = +2.
These are +9 and - 7 so
Answer is 2(x - 7)(x + 9).
3. -30x^3 + 3x^2 + 9x
First we can take out -3x to give
-3x(10x^2 - x - 3)
Now we want 2 numbers whose product is 10*-3 = -30 and whose sum is -1. They are -6 and +5 so we write the above as:
-3x(10x^2 + 5x - 6x - 3)
Now we factor the parentheses by grouping:
= -3x( 5x(2x + 1) - 3(2x + 1)
= -3x(2x + 1)(5x - 3) Answer.
The answer to the second part is 12x^2 - 13x - 21.
Part 3
1, 18.
2. 6.
3. = 5(2(-3)^2 - 3*3*4 + 4^2) - 3)) - 2(-3)(-3 + 7(4) - 1) - 3*4^2
= 5*(67) - 2(72) - 48
= 143.
4. (11m^2 - 7) - (6m^2 + 3m - 11) + (3m^2 - m - 9)
= 11m^2 - 7 - 6m^2 - 3m + 11 + 3m^2 - m - 9
= 8m^2 - 4m - 5
A = 8, B = 4 and C = 5.