The student would have to score 100% on their next test to brung their average up to 90. Here is why;
90+84+86=260
(260+?)/4=90
(260+100)/4=90
360/4=90
This is done to get the mean (or average) of a group of numbers by adding all the numbers and dividing by the amount of numbers you added together. Here it is divided by 4 because of the three tests he has taken and the test he will take.
Answer:
He is asking about the power not the answer. I did a small calculation like 8*3 should be a 2 digits number. Took 10^1 out & simply 10^1*10^12*10^2= 10^15
Answer:

Step-by-step explanation:
7x + 24x = 25 x
31 x = 25 x
Subtracting 25x to both sides
31x - 25x = 0
6x = 0
Dividing both sides by 6
=> x = 0
54+36=90<span>90÷6=15
So 15 is your answer</span>