Question

7x-x+8x=?

Answer 1

x is common to all three terms so if you factor it out, you'll have:

(7 - 1 + 8)x

You can simplify from there by adding/subtracting

Answer 2

notice how everything here is multiplied by x? you can rewrite this as:

x (7-1+8)= x(14) = 14x

Answer 3

If you have trouble understanding why we can combine the x, just pretend that x is any number.