I'd first explain how expansion works, and that the first step is to expand the first bracket as shown below:The first bracket expands to: 5x + 5y which equals 5x + 5yThe next step I'd show would be the expansion of the 2nd bracket, much like the step above. The second bracket expands to 34x + 3(-2y) which equals 12x - 6y
The next step is to simplify the equation as shown below:First collect all the like terms together (ie all the x's and all the y's) so:(5x + 12x) + (5y + (-6y))= 17x -y