if r = -4 find the value of 3r - 9.
3 × -4 -9=-21you know r so its just fill in
The answer is -21. You fill in the r with -4 and you multiply 3 with -4 which is -12. Then subtract 9 from -12 which is the same as -12+-9 which is equaled to -21. Hope this helps.
