Question

Dacă X+Y=10 si Y+2xZ=12 calculează 3X+8Y+10Z

Answer 1

x+y = 10 ⇒ x = 10-y
y+2z = 12 ⇒ y = 12-2z

3x+8y+10z = 3(10-y)+8y+10z = 30-3y+8y+10z = 30+5y+10z = 30+5(12-2z)+10z = 30+60-10z+10z = 90.