Answer:
60/220
Step-by-step explanation:
we use combination,


then, all divided by,


Answer:
Step-by-step explanation:
The equation is:
√b+20 - √b = 5
The first step is we will add √b to both sides:
√b+20 -√b +√b = 5 +√b
√b+20 = 5+√b
Now take square at both sides:
(√b+20)^2 = (5+√b)^2
b+20 = 25+10√b+b
Now combine the like terms:
b+20-25-b=10√b
-5 = 10√b
Divide both the terms by 10
-5/10 = 10√b/10
-1/2=√b
Take square at both sides:
(-1/2)^2 = (√b)^2
1/4 = b
So in this type of question we add radical terms to both sides and square both sides twice....
Answer:
82
Step-by-step explanation:
The sum of scores for the 9 tests must be 90 * 9 = 810. The sum of scores for the 8 tests is 8 * 91 = 728 so the lowest score is 810 - 728 = 82.