(((15-x)*3)/1000)+(((1--x)*5)/1000)=x/500
16x^2 +48xy + 36y^2
x/28 + 87 = 479
15+10x=13x
(2x+1 ) times (x+1)
2x*3y*2xy
is 165 a prime number
x over 6 + 7 over 15
$0.2^{4}$
2^1÷7=1+x÷100