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Question 26225: 7-3(5t-10)+67
is the answer t=6 or t=2
Do I take -3x5t and -3x-10 or just 3x5t and 3x-10. I always get that mixed up.
Do you have an tips for me in algebra.
Thank you for your help
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! there is no answer for t, since you do not have an equation... no equals sign.
To simplify 7-3(5t-10)+67, we do the following:
7-3(5t-10)+67
7-15t+30+67
90-15t
or 15(6-t) as a factorised version.
How to do it?
the full expression is +7 + -3*(+5*t + -10) + +67
the brackets tell you to multiply the -3 by +5t and by -10, giving
+7 + -15t + +30 + +67
now in places we have 2 signs together (since we use + and - for 2 seperate things --> ADD-SUBTRACT and also POSITIVE-NEGATIVE.
So, rules are: +- or -+ can be thought of as SUBTRACTING ie + -15t is just -15t
and ++ or -- can be thought of as ADDING
so,
+7 - 15t + 30 + 67
which gets you the same answer i gave... my version above is done without writing all the signs out, because "we do not need them, because we know which ones are not written". Obviously, learning algebra, you need to learn the fact that some are missing and "put them in, in your head".
I hope that helps?
jon.
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