Answer:
1. 6x^2 + 4x - 4y
2. x - 10y.
3. 6x^5
4. 36 a^6 b^8
5. x^2 - 81
6. 9x^2 - 42x + 49
7. 12x^2 +3x - 42
Explanation:
1. 3x^2+4x+3x^2-4y
Add the like terms, we get
6x^2 + 4x - 4y
2. (5x-2y)-(4x+8y)
Now distribute the negative sign, we get
5x - 2y -4x -8y
Simplify the like terms, we get
x - 10y.
3. 3x^3(2x)^2
Multiply the numbers and simplify the variables
6x^(3 +2)
6x^5
4. (-6a^3b^4)^2
Now bring the power 2 inside the parenthesis.
-6^2 a^6 b^8
= 36a^6b^8
5. (x+9) (x-9)
x^2 + 9x -9x - 81
x^2 - 81
6. (3x-7)^2
(3x - 7)(3x - 7)
9x^2 - 21x -21x + 49
9x^2 - 42x + 49
7. (3x+6) (4x-7)
12x^2 + 24x -21x - 42
12x^2 +3x - 42
Thank you.