SOLUTION: Really need help on this problem please! Decide whether 4[ -10+9(-1)] less than 70 true or false

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Question 825421: Really need help on this problem please!
Decide whether 4[ -10+9(-1)] less than 70
true or false

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
4[-10+9(-1)]=4[-10+(-9)]
=4(-19)
=-76<70

Really, there was no need to calculate,
because the product of a negative number and a positive number is negative,
so 9(-1)<0 .
Then, added to -9, we get the sum of two negative numbers, which is negative:
-10+9(-1)<0 .
Then the negative number [-10+9(-1)] , multiplied by 4 is negative.
That means
4[-10+9(-1)] < 0 ,
and since 0 < 70,
4[-10+9(-1)] < 70 .