The geometric mean of two numbers x and y is √(xy).
So, if the geometric mean of 3 and a is 9 =>
9 = √(3a)
=> 9^2 = 3a
=> a = 9^2 / 3
a = 81 / 3
a = 27
Answer: the value of a is 27.
2x+3=17
subtract 3 from each side
2x+3 -3 = 17 -3
2x = 14
divide by 2 on each side
2x/2 = 14/2
x = 7
60 = (10 + 20 + 30 + 40 + x)/5
300 = 100 + x
x = 200
Answer: 200