Question

calcule mentalmente o valor de x:

a)x+5=7

b)x+12=10

c)x-5=6

d)9x=27

Answer 1

a)
x+5=7
x=7-5
x=2


b)
x+12=10
x=10-12
x=-2


c)
x-5=6
x=6+5
x=11



d)
9x=27
x=27/9
x=3