Step-by-step explanation:
Total books = 368.
Sociology books = 92.
Psychology books = 3 times sociology books
= 3 x 92 = 276
Total = 276 + 92 = 368
Answer:
r = -39
Step-by-step explanation:
So we are trying to solve the equation for r.
-6(2r + 8) = -10(r - 3)
Divide both sides by -2. (This will make distributing much easier.)
3(2r + 8) = 5(r - 3)
Distribute the 3 on the left side and the 5 on the right side,
6r + 24 = 5r - 15
Subtract 24 from both sides.
6r = 5r - 39
Subtract 5r from both sides.
r = -39
So now we have solve the equation.
I hope you find my answer and explanation to be helpful. Happy studying. :)
(4,10).
1. There are three ways to solve this: elimination, substitution, graphing.
2. I chose elimination, so I had to get one negative variable and one positive variable of the same value (for example, 18 and -18)
-7x+2y=-8
-16x+9y=26
I chose to get 2y and 9y to equal -18y and 18y.
So, multiply the first equation by -9. Multiply the second by 2.
63x-18y=72
-32x+18y=52
the 18s cross each other out. So you're left with
63x=72
-32x=52. Add them.
31x=124, divide both sides by 31, and you'll get 4.
x=4
Plug your answer for x into one of the equations. Let's use the first one.
-7(4)+2y=-8
-28+2y=-8. add 28 to both sides.
2y=20, divide both sides by 2.
y=10.
This makes your answer (4,10)
Answer:
Use a spreadsheet.
Step-by-step explanation:
If you mean a household budget you could use a spreadsheet.
The columns would be months and the rows would be items of expenditure and income.
You use formulae ( provided by the spreadsheet) to do additions, subtractions and so on.
