Question

Help, its just two questions...

Answer 1

In Q39, the value 3x should be positive and in Q40, the final answer is missing 8x and the fact that 4x^2 is negative (-4x^2)

Explanation:

39:

1.
`-(-3x)` is presented as
`-3x` when it should be
`+3x`, as 2 negatives make a positive.

2. Again,
`-3x` is shown instead of
`+3x`

3. The answer
`-x^2-2x` should instead be
`-x^2+4x`, as
`-3x` is used to reach this incorrect answer instead of the correct
`+3x`

40:

1.
`(x^3-4x^2+3)+(-3x^3+8x-2)=(x^3-3x^3)-4x^2+8x+(3-2)=-2^3-4x^2+8x+1`,

The final answer is wrong as it is missing the 8x and the fact that it is
`-4x^2`and not
`+4x^2`