Answer:
x=6
Step-by-step explanation:
We have the equation 12+3x=30, we need to calculate the value of x:
[tex]12+3x=30[/tex], subtract 12 in both sides
[tex]12+3x-12=30-12[/tex]
[tex]3x=18[/tex], divide both sides in 3
[tex]\frac{3x}{3}=\frac{18}{3}[/tex]
[tex]x=6[/tex]
Now to see if this statement is true we have to replace in 12+3x=30 with x=6,
[tex]12+3x=30\\12+3.6=30\\12+18=30\\30=30[/tex]
Then x=6 makes the sentence true.
