20 points

using the substitution method, solve the following equations.
1.) m+n=5
m-n=3
2.) y=3x-7
6x-2y=12
3.) 5x+2y=7
y=x+7
4.) y+2x=7
14 - 4x=2y
5.) y=4x+6
5x-y=6

1. jesus bought 3 pairs of jeans for $71.40. how much would he need to pay for 8 pairs of jeans? unit rate $ pair cost for 8 2.morgan scored 41 points in 3 games. how many points would you expect him to make in an 11 game season? unit rate points/game points in 11 games 3. andy drove 840 miles in 12 hours. how far could he drive in 3 hours? unit rate (speed) distance 4. pira drives 825 miles to california. the trip takes him 17 hours. he uses 38 gallons of gas on the trip, which costs him $125? a) find his speed b) find his gas mileage c) find the unit price he paid for gas me this is due ! explanation for each one ! ! ! ! someone