What solution is 13t + 4 = 12 + 3t

Start by subtracting 3t from both sides of your equation

13t+4=12+3t

-3t. - 3t

that gives you

10t+4=12

Subtract 4 from both sides

10t+4=12

-4. - 4

That gives you

10t=8

Divide both sides by 10 to leave the variable by itself

10t=8

:10. : 10

That leaves you with

t=8/10 or t = 4/5 if you simplify.