How do you solve #7- 3( 5t - 10) = 67#?

1 Answer
Sep 21, 2016

Answer:

Distribute the #-3# first.

Explanation:

You may be tempted to subtract #7# and #3# but that is the wrong thing to do. Subtracting #3# is the same thing as a negative #3#, so we should distribute the #-3# to everything in the parenthesis.

Distributing the #-3#:

  • Multiply #-3# by #5t# to get #-15t# and multiply #-3# by #-10# to get positive #30#

#7-15t +30=67#

The #7# and the #30# both have no variable, so these can be combined.

#7+30=37#

Now we're left with

#37-15t=67#

The next step would be to subtract #37# from both sides. Remember, the goal with these kinds of equations is to isolate the variable to get our answer. #37-37# cancels out, and #67-37# is #30#.

We're left with

#-15t= 30#

When a variable term is equal to a constant term, you always divide by the coefficient of the variable (number in front of variable).

The coefficient is #-15#. Dividing #-15t# by #-15# will just leave #t#, and #30/(-15)# is equal to #-2#. This means

#t= -2#

I'm in the 9th grade and I did a problem like this today :)