math ALGEBRA 1 PLEASE HELP!
posted by alex .
You have $2.75 in dimes and quarters, and you have a total of 17 dimes and quarters. How many of each type of coin do you have?

D+Q=17
or Q=17D
and 10D+25Q=275
or 10D+25(17D)=275
solve for D, then solve for Q 
Distribute 25
10D+42525D=275
Add like variables
42515D=275
Subtract 425
15D=150
Divide Each Side by 15
D=10
Plug D into equation to solve for Q.
Q=1710
Q=7