6xx1 21 x solving equation by factoringSolution6xx121x 6x2

6x(x-1) = 21 - x
solving equation by factoring

6x(x-1)=21-x
6x^2-6x=21-x
6x^2-6x+x-21=0
6x^2-5x-21=0
factor 6 into 3*2 and factor 21 into 7*3
group the 3 with the 3 and the 2 with the 7 to get 3*3=9 and 2*7=14
14-9=5(the middle term disregarding signs)
(3x-7)(2x+3)=0
3x-7=0 and 2x+3=0
3x=7, x=7/3
2x=-3, x=-3/2