Question

Afla numerele x,y,z,stiind ca:
x+y=142 y+z=90. x+z=156

Answer 1

x+y=142;=>y=142-x
 y+z=90=>z=90-y
x+z=156
x+90-y=156
x+90-142+x=156
2x-52=156
2x=208
x=104
y=142-104
y=38
z=90-38
z=52

Answer 2

2X+2y+2x=142+90+156 =232+156 =338 X+y+z=338÷2 =169 Z=169-142=27 y=90-27=63 X=142-63=79