4x-2y=7 (1)
-3x+3y=10 (2)
3y= 3x+10
y= x+10/3 (3)
sub (3) into (1)
4x-2(x+10/3)=7
4x-2x-20/3=7
2x-20/3=7
+20/3 +20/3
2x= 41/3
x= (41/3) / 2
x= 41/6
sub x= 41/6 into (3)
y= 41/6+10/3
= 61/6
Therefore the point of intersection is (41/6, 61/6)
10.
a) x- is the time after which the total cost is the same.
24 + 99x - is the cost in the dealership
45 + 89x is the cost at the local mechanic
24 +99x = 45 + 89x
99x - 89x = 45 - 24
10x = 21
x= 2.1 (hours)
b) 24 +99x < 45 + 89x
x< 2.1
The repairs cost less in dealership when work takes less than 2.1, and the dealership is better, because the cost of parts is less in the dealership.
Speed = distance / time
Speed = 50 miles / 4 hours
Speed = 12.5 miles per hour
That person is really smart good job
