Le A et B please EQUATIONS 4EMES

Ex 3 :
4x = 36
x = 36/4
x = 9

3y = - 21
y = - 21/3
y = - 7

18 = - 4a
4a = - 18
a = - 18/4
a = - 9/2

4/5m = 2/3
4m * 3 = 2 * 5
12m = 10
m = 10/12
m = 5/6