Answer: 
<u>Step-by-step explanation:</u>

NOTE: The sign between 4x and 7 is missing in the question you posted. I assumed it was 4x + 7 in order to solve the equation.
Answer:
6⅔ minutes
Or, 6 minutes 40 seconds
Step-by-step explanation:
X/10 + X/20 = X/T
(2X+X)/20 = X/T
3X/20 = X/T
3/20 = 1/T
T = 20/3
T = 6⅔ mins
Answer:
79%
Step-by-step explanation:
He has 100% to start off. If he puts 21% into savings you subtract that from the starting amount. 100 - 21 = 79. Therefore the answer is 79%.
5.10÷85=$0.06<---
check your answer
85×0.06=$5.10
Answer:
-6
Step-by-step explanation:
this is in y=mx+b form, where m is the slope ! so m is -6