25+95=120 25(notes on)=95(no notes on)=120 total
First, find what one lightbulb costs.
9.85 / 5 = 1.97
Then multiply the product by 7.
1.97 * 7 = 13.79
Seven light bulbs will cost $13.79
If you have a problem like:
4x+2y=20
2x+2y=16
You would subtract
4x-2y=20
-2x+2y=16
You would get the new problum
2x=4
You now want to divide the 2 on both sides to solve for x
x=2
Now that you've solved for X you want to solve for y. So use substitution to solve for y. You would want to substatute the x for the 2 in either of the problums. I'll use the first one.
4(2)+2y=20
You first want to multiply te 4(2) you would get a new problum.
8+2y=20
Now you want to subtract the 8 on both sides.
2y=12
The last step to solve for y is to divide the 2 on both sides.
Y=6
So your answers would be
x=2
y=6
5,040 I think because 7•6•5•4•3•2•1=5040
