Answer: 66.50+5g= 83.50
g=3.4
Step-by-step explanation:
Simply it as follows:
1 + 39 = 40
2 + 38 = 40 etc
18 + 22 = 40
19 + 21 = 40
There are 19 of these plus 40 itself . . .therefore 20 of them
20 x 40 = 800
And finally the last number not used, 20
Therefore 800 + 20 = 820
Y = -X + 7
Y = .5(X-3)2
Alright check it out. Substitute the Y in the second equation for the first equation so...
-X + 7 = .5(X-3)2
After this, you have to get rid of the .5 and the 2 which is easy peasy because they just cancel out. If you were to multiply by half and then multiply by 2 then you'd be back to where you started. So...
-X + 7 = X - 3
Move the X to combine them on one side, I moved the -X to the opposite side by adding X to each side so you get...
7 = 2X - 3
You then add 3 to both side so...
10 = 2X
Divide by 2
X = 5
So...
Y = -5 + 7
Y = 2
Y = .5(5-3)2
Cancel out the .5 and the 2
Y = 5-3
Y = 2
(5,2) is your answer
