Question

afla nr necunoscut 11-(7×5-9×9:f:3):8=7

Answer 1

11-(7×5-9×9:f:3):8=7
-(35-81:f:3):8=-4
35-81:f:3=32
-81:f:3=-3
81:f=9
f=81:9=9

Answer 2

11-(7×5-9×9:f:3):8=7
-(7×5-9×9:f:3) :8 = 7-11
-(7×5-9×9:f:3) = -4×8
-35+9×9:f:3= - 32
9×9:f:3 = 35-32
9×9:f = 3×3
9×9:f =9
9×f = 9×9
9×f = 81
f = 81:9
f = 9