Well, lets first start off with combining like terms.
9x + 26 + 7x - 17 = 2x + (-3x) + 5x
9x + 7x + will give you 16x, and 26 - 17 will give you 9. Therefore, the first part of the equation is 16x + 9.
On the other side, you can combine all three terms (2x + 5x - 3x), which will give you 4x.
Using the above steps, you can figure that the answer is 16x +9 = 4x