Question

Aflati numarul necunoscut "m" din egalitatea: (6×6+21:m)-2×8:4+(20-5×3)=2×4×5

Answer 1

2x4x5=40

20-5x3=5

2x8:4=4

-2x8:4+(20-5x3)=1

6x6+21:m=40-1=39

36+21:m=39

21:m=39-36=3

m=21:3=7

Answer 2

( 6 × 6 + 21 : m) - 2 × 8 : 4 + ( 20 - 5 × 3 ) = 2 × 4 × 5

( 36 + 21 : m ) - 16 : 4 + ( 20 - 15 ) = 8 × 5

( 36 + 21 : m ) - 4 + 5 = 40

36 + 21 : m = 40 - 5 + 4 → metoda mersului invers

36 + 21 : m = 35 + 4

36 + 21 : m = 39

21 : m = 39 - 36

21 : m = 3

m = 21 : 3

m = 7