Answer:
199 if it's 7b^3 + 10
9271 if it's (7b)^3 + 10
Step-by-step explanation:
You just substitute the 3 in for d. If your expression was 7b^3 + 10, then only b is being raised to 3.
So 3^3 is 27, 27*7 is 189, 189+10 is 199.
If the expression was (7b)^3 + 10, then first you multiply 7 and 3 to get 21. Then you raise 21 to the power of 3, which is 9261. Then you add 10, which is 9271.
To check if x = 9 is the solution, we need to replace every x with 9 and simplify
(3+x)/4 = 3
(3+9)/4 = 3
12/4 = 3
3 = 3
We get the same thing on both sides, so the last equation is a true equation. This means that the first equation is a true equation when x = 9. Therefore, the solution x = 9 is confirmed.
65 - 30 - 21 = 14
(sixty-five minus thirty minus twenty-one equals fourteen)
Answer:
9.55 minutes
Step-by-step explanation:
x hours to go to the river
0.25-x hours to come back, since 15 minutes is 0.25 hr.
to the river 40 mph * x hours =40x miles
from the river 70 mph (0.25-x) hours=17.5-70x
those two are equal
40x=17.5-70x
110x=17.5
x=17.5/110=0.159 hours
9.55 minutes
