Question

x+2y=17
y-3z=4
calculati (2x+4y)*(x+4y-6z)

Answer 1

x=17-2y
y=4+3z
-3z=4-y⇒z=$\frac{4-y}{-3}$
2(17-2y)+4(4+3z)*17-2y+4(4+3z)-6($\frac{4-y}{-3}$)
34-4y+16+12z*17-2y+16+12z-6/$\frac{4-y}{-3}$=34+16*17+16-6/$\frac{4-y}{-3}$-4y+12z-2y+12z=$\frac{-645}{1-y}$-6y+24z;