for number one if y=6x you replace that in the equation so it would be 2x+3(6x)=20 which then ylu can solve normaly with PEMDAS so you would first multiply 3 and 6x to get 18x so your equation is now 2x+18x=20 then you would add the x's so it would be 20x=20 then you devide both sides by 20 which would leave you with the answer of x=1 :) then you need to find y which you now put the x into the ecuasion where it goes which means you would have the ecuasion of 2(1)+3y=20. again use PEMDAS and multiply 2•1 so you would then have the equasion of 2+3y=20 which then you have to subtract the 2 from both sides which would leave you with 3y=18 then you divide by three on both sides which leaves you with y=6 so the final answer would be (1,6) :)