due to the more than usual numbber of questions in a question, we will have shortened explanations
questions an answes are as follows:
1. 5x+8y=7300 and 1250=x+y
2. y=4x+45 and x=4y
3. y+11=2x and 3y-6y=-33
1.
5x+8y=7300 and 1250=x+y
multily 2nd equation by -5 and add to othe equation
3y=1050
divide both sides by 3
y=350
sub back
x+y=1250
x+350=1250
minus 350 both sides
x=900
(900,350)
2.
sub 4y for x
y=4(4y)+45
y=16y+45
minus y both sides
0=15y+45
minus 45 both sides
-45=15y
divide both sides by 15
-3=y
sub back
x=4y
x=4(-3)
x=-12
(-12,-3)
3.
y+11=2x
3y-6x=-33
divide last equation by 3
y-2x=-11
add 2x to both sides
y=2x-11
add 11
y+11=2x
same equation
infinite solutions
all points on y=2x-11 are solutions
1.(900,350)
2. (-12,-3)
3. infinite solutions, any point on y=2x-11
