Thread: Distributive Property, exponents, combining like terms, and negative numbers

Ok, i did this problem in several methods we've been taught, but none of them reached the answer in the check your work section. As it was the last one with the given answer, and i was so far off in the answer, i'm worried about the remaining ones done in that method. heres the problem i cant get the book answer to:
Apply the distributive property. Then simplify by combining like terms.
65. 7x - 3x(x + 1)
Answer in book: 4x - 3x squared
and heres the problems im nervous about
66.-4(y + 2) - 6y
67.3t(t - 5) + 6t squared
68.-x cubed + 2x(x - x squared)

Thanks in advance
Note: 'squared' means raised to the second power, and 'cubed' means to the third power. i dont know how to make the floating 2 or 3 symbol.

65. 7x - 3x(x + 1)
66.-4(y + 2) - 6y
67.3t(t - 5) + 6t squared
68.-x cubed + 2x(x - x squared)

Exponents can be expressed like this

t squared = t^2

x cubed = x^3

Just one piece at a time.

7x - 3x(x + 1) = 7x - 3x^2 - 3x = 7x - 3x - 3x^2 = 4x - 3x^2

-4(y + 2) - 6y = -4y - 8 - 6y = -8 - 4y - 6y = -8 - 10y

You show us the next one.