What is the value of 3t+7 when you know -21t+1=3

I need to know how to figure this out not just the answer. Thank you

2 answers

3/3 + 7/3
t= 2.3333333333333
we know -21t+1=3
-21t = 2
t = -2/21

then 3t+7
= 3(-2/21) + 7
= -2/7 + 7
= 47/7