Hello!
First, think of the minus sign as being -1:
-1(-2x+3-7r)
Now, distribute it by multiplying it times -2x and 3 and -7r
2x-3+7r
Can we simplify this expression any further? Nope.
2x, -3 and 7r are not like terms, so we cannot combine them.
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Extra note
A negative times a negative is a positive.
Hope everything is clear.
Let me know if you have any questions!
#KeepLearning
:-)