[tex]\sf 4m-21=3(5m-1)[/tex]
First, distribute 3 into the parenthesis(multiply it to every term inside):
[tex]\sf 4m-21=15m-3[/tex]
Add 21 to both sides:
[tex]\sf 4m=15m+18[/tex]
Subtract 15m to both sides:
[tex]\sf -11m=18[/tex]
Divide -11 to both sides:
[tex]\sf m=-\dfrac{18}{11}[/tex]
To check our work we can plug this back into the original equation for 'm':
[tex]\sf 4m-21=3(5m-1)[/tex]
[tex]\sf 4(-\dfrac{18}{11})-21=3(5(-\dfrac{18}{11})-1)[/tex]
Multiply:
[tex]\sf -\dfrac{72}{11}-21=3(-\dfrac{90}{11}-1)[/tex]
Distribute 3 into the parenthesis:
[tex]\sf -\dfrac{72}{11}-21=-\dfrac{270}{11}-3[/tex]
Subtract:
[tex]\sf -\dfrac{303}{11}=-\dfrac{303}{11}~\checkmark[/tex]
Both sides are equal to each other, so we solved it correctly.
