Question

determinati nr x daca media aritmetica a nr x, 9 si 2x este 7

Answer 1

(x+9+2x):3=7
3x+9=21
3x=21-9
3x=12
x=12:3
x=4

Answer 2

(x+9+2x)/3=7
(9+3x)/3=7
3+x=7
x=4