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
3648500/103
3x^{2}+x=4
(-1/2)^4-3*(-1/2)^3-2*(-1/2)^2+5