-4r-11=4r+21
Move 4r to the other side
Sign changes from +4r to -4r
-4r-4r-11=4r-4r+21
-4r-4r-11=21
-8r-11=21
Move -11 to the other side
Sign changes from -11 to +11
-8r-11+11=21+11
-8r=21+11
-8r=32
Divide both sides by -8
-8r/-8=32/-8
Answer: r=-4
Answer:
r=32/7
Step-by-step explanation:
Hello! Your answer is B, 10 minutes.
Say the x = minutes taken to do the job. You can set up an equation like this to solve this.

This is representative of the situation. The fractions each represent <u>how much each person does in a minute</u>, and when they're multiplied by x, that's <u>how much of the project they get done</u> based off of the minutes they work together on the job. Add the two together, and you get <u>how much of the project is finished in x amount of time</u>. Set it equal to 1, as you are looking for 100% completion.
Once you have this equation, find a common denominator, add, and solve.





Therefore, it will take them 10 minutes to do the job together.
Hope this helps!
637 is the answer because our value is 980 we all know the unknown value with x for the step above 980 and 100% and 65% is the result in a pair of a simple equations