Question

Stiind ca x=5 si y+z=14,calculati:
a)x+2y+2z
b)5x+3y+3z

Answer 1

x=5  si    y+z=14

 a)  x + 2y + 2z = x+2(y+z) = 5 + 2×14 = 5 + 28 = 33

b) 5x + 3y + 3z = 5x + 3(y+z)= 5 × 5+3 ×14 = 25 + 42 = 67

Answer 2

a)x=5, y+z=14⇒y=14-z
    x+2y+2z=0⇔5+14-z+2z=0⇔19+z=0⇒z=-19
    y=33

b)5x + 3y + 3z = 5x + 3(y+z)= 5 * 5+3 *14 = 25 + 42 = 67