Solve the system of equations using elimination:
x+4y-5x=-7
3x+2y+3z=7
2x+y+5z=8

Using elimination: add equation 1 and equation 3 to eliminate z
x+4y-5z=-7
2x+y+5z=8
will result to
3x + 5y = 1  

Using eqution 2 and 1.
3( x+4y-5z=-7) >> 3x +12y – 15z = -21
5(3x+2y+3z=7) >> 15x + 10y + 15z = 35
Add the two equation, to eliminate z
18x + 22y = 14  

Solving x and y from the generated equation
X = 2
Y = -1   T
hen substitute x and y yo any equation and solve for z
Z = 1