Question

Afla numarul necunoscut:1) a:(80-72)=5 ;2)3×4+a=18 ;3)4×a+25=45;4)32:a-2=6

Answer 1

a) a : ( 80 - 72) = 5
    a : 8 = 5
    a = 5 x 8
    a = 40.

b) 3 x 4 +a = 18
    12 +a = 18
     a = 18 - 12
     a = 6.

c)  4 x a + 25 = 45
     4 x a = 45 - 25
     4 x a = 20
      a = 20 : 4
      a = 5.

d) 32 : a - 2 = 6
    32 : a = 6 +2
    32 : a = 8
    a = 32 : 8
    a = 4.

Answer 2

1. a:(80-72)=5 a:8=5; a=8×5; a=40; 2. 3×4+a=18 12+a=18; a=18-12; a=6; 3. 4×a+25=45 4×a=45-25; 4×a=20; a=20:4; a=5; 4. 32:a-2=6 32:a=6+2; 32:a=8; a=32:8; a=4.