Question

The cost of 3 notebooks and four pencils is $8.50. The cost of 5 notebooks and 8 pencils is $14.50. Determine the cost of one notebook and the cost of one pencil. Only in algaebraic solution.

I guess it is 3n +4p =8.50
5n+ 8p=14.50

Then I am stuck

Answer 1

lets try and eliminate one variable by adding the equations together
if we multiply the first equation by -2 we will get -8p
- 8p +8p=0p

ok lets do that
-2(3n +4p=8.50)
-6n-8p =-17.00added to
5n+8p = 14.50 leaves us with

-n= -2.50 or n=2.50
pluggung in one equation
3(2.50) +4P = 8.50
7.50 +4P = 8.50
subtract 7.50 from both sides
7.50-7.50)+ 4P = 8.50-7.50
4P = 1.00
divide both by 4
P=.25

you can do a check with the other equation

Answer 2

Ok thank you soo much!