45x-10y-30z=15
10x-100y+50z=0
30x+50y-100z=0
j=1
∑
n
j
4
2x - 5 = 3x + 7
6-(56-40)/(2*4)+5=
4x+5(6+3x)=11
solve for x and y
83/5 divided 2
13/15
$\sqrt{\Box}$ 144
