The solution of X + 2.2x = 480

The solution of X + 2.2x = 480


X + 2.2x = 480, so 3.2X = 480, x = 480 / 3.2 = 150



(20 + 2x) (30 + 2x) = 3000


(20+2x)(30+2x)=3000
=>4x^2+100x+600=3000
=>4x^2+100x-2400=0
=>x^2+25x-600=0
=>(x-15)(x+40)=0
x1=15 x2=-40