Solving an absolute value equation and the defference between two quadratics

[drop]

Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :)

PART A

9) Solve for all X: |2x-5| + 3 = 18

My Answer: x = 10, x = -5

10) Subtract and simplify: (5x^2 - 3x + 8) - (-4x^2 - x + 10)

My Answer: 9x^2 - 2x - 2

 

[MarkFL]

Re: Please check my answers - 5

9.) Correct.

I would be inclined to write this equation as:

$$|x-2.5|=7.5$$

Now we can see that $x$ is a number whose distance from 2.5 is 7.5 units, or:

$$x=2.5\pm7.5\implies x=-5,\,10$$

10.) Correct.