Substitute y=6x-4 into the equation 3x+6y=15 to eliminate y.You will then have the equation 3x+6(6x-4)=15.The next step is to expand the brackets given 3x+36x -24=15.The next step is to collect like terms, so lets start with the x's, given 39x-24=15.The next step is to collect like terms, so lets collect the numbers given 39x=39.To find x you need to divide by 39 on both sides given x=1.Now you have a value for x you can use this in your original equation. Substitute x=1 into the equation y=6x-4 given y=6(1)-4. This gives y=2.Therefore the answer is coordinate (1,2)