What is the value of -9r-7 when r=2?
-25
-18
11
45

First plug in 2 for r like so:

-9(2) - 7

To solve this you must use the rules of PEMDAS (Parentheses, Exponent, Multiplication, Division, Addition, Subtraction)

REMEMBER: IF NOT APPLICABLE TO THE EQUATION YOU MAY SKIP THAT STEP IN PEMDAS .

First we have multiplication:

-9(2) - 7

-9(2) = -18 <<< When multiplying a negative and positive number together you will multiply normally and the answer will have a negative sign

-18 - 7

Now for the subtraction:

-18 - 7 <<< When subtracting with a negative number you will do something called "Same-Add-Opposite." This means that you will keep the first number in the expression (in this case that is -18) the same. Then turn the subtraction sign into an addition sign. Finally you will take the "opposite" sign of the second number. When I say "opposite sign" I mean that if this number is positive it will become negative. If it was negative it will become positive.

Here is your expression after applying same - add - opposite:

-18 + (-7)

-25

Hope this helped!

~Just a girl in love with Shawn Mendes

the answer is -25

all work is shown