Answer:
x^2 -81
Step-by-step explanation:
(x+9)(x-9)
FOIL
first x*x = x^2
outer -9x
inner 9x
last -9*9 = -81
Add them together
x^2 -9x+9x -81
Combine like terms
x^2 -81
Answer:
Mark is 9 years old.
Step-by-step explanation:
If Mark Bro is 5 years older and combined is 23, then you want to subtract 5 from 23 giving you 18. Now since there is mark and his brother that is 2. So divide 18 by 2 and you get 9. Mark is 9. Add 5 to the other 9 because mark is 9 and we divided by two so one nine still remains you get (14). Now you can check. Marks age plus his brothers 9+14=23.
Equation: mark=m
m = (23-5)/2
m=18/2
m=9
Answer:
This would be true. in order to find the mid-point of any two given points you have to add both x and y coordinates and divide by two.
I think you should try your best and just never get but just always keep trying because if you give up that means you're not track so just keep trying and get it right.