Упростите выражение:

1) 7x (x-4) - x (6-x)

2) 5ab (4a+3b) - 10 а^2 (2b-4)

3) xy (2x-11y) - x (xy+14y^2)

4) 5c^3 (4c-3) - 2 с^2 (8 с^2-12)

7x (x-4) - x (6-x) = 7x²-28x-6x+x²=8x²-34x

5ab (4a+3b) - 10a² (2b-4) = 20a²b+15ab²-20a²b+40a²=15ab²+40a²

xy (2x-11y) - x (xy+14y²) = 2x²y-11xy²-x²y-14xy²=x²y-23xy²

5c³ (4c-3) - 2c² (8c²-12) = 20c⁴-15c³-16c⁴+24c²=4c⁴-15c³+24c²