
if you have already covered slopes, you could also get it that way, in fact is simpler that way.
Ok so right now leave the x's alone. Now add/subtract the numbers without variables which would equal to 0 since -1+4 = 3 and 3-3 =0
now 7x+x =8x so 8x is answer
20,000,000+400,000+80,000+4000+100+60+3