Answer:
here is your answer
hope it help you
36.50
Step-by-step explanation:
just add them all up
85
The 9 th square number is 9² = 81
The 2 nd square number is 2² = 4
sum = 81 + 4 = 85
(x+1)^2-x^2=23
x^2+2x+1-x^2=23
2x+1=23
2x=22
x=11
11^2 = 121
x+1 =12
12^2=144
144-121 = 23
