How do you evaluate #2( - 9) + 7( - 8)#?

1 Answer
Suren Abreu
Jun 28, 2017

#-74#

Explanation:

#2(-9)+7(-8)#

There are two multiplications here, each involving a positive and a negative number. When a positive and a negative number are multiplied, the answer will always be in the negative.

We shall segregate the two for easier understanding.

#[2xx(-9)]+[7xx(-8)]#

Now #2xx9=18# and #7xx8=56# and both these will take a negative sign so we can write:

#[-18]+[-56]#

Since the minus sign is common, we can write:

#-[18+56]#

Adding the two numbers in the square brackets, we get:

#-[74]#

Removing the square brackets:

#-74#

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