Answer:
4c+ 2m = 7.90
2m -.15 = c
Step-by-step explanation:
Let c = cheese burger
m = milkshake
4c+ 2m = 7.90
2m -.15 = c
Substitute into the first equation
4( 2m -.15) +2m = 7.90
Distribute
8m -.6 +2m = 7.90
Combine like terms
10m - .6 = 7.90
Add .6 to each side
10m = 7.90+.6
10m = 8.50
Divide by m
10m = 8.50/10
m = .85
Now find c
2m -.15 = c
2(.85) - .15=c
1.70-.15 = c
1.55 =c