Question

x + y = 6
2x + y = 4
Solve the system of equations by substitution.


(-2, 8)
(2, -8)
no solution
coincident

Answer 1

x + y = 6----(1)
2x + y = 4---(2)

in equation (1)
x+y=6
x=6-y

put in equation (2)
2(6-y)+y=4
12-2y+y=4
12-y-4=0
y=8

put these value of y in equation (1)
x+8=6
x=6-8
x=-2

so solution (x,y)=(-2,8)

Answer 2

what about this one?

7x - 2 = 2y
3x = 2y - 1
Solve the system of equations by substitution.


(3/4, 13/8)
(1/4, -1/8)
no solution
coincident

Answer 3

7x-2=2y---(1)
3x+1=2y---(2) SUBTRACT EQUATION (1) and (2)
----------------
4X-3=0
4X=3
X=3/4

put the value of x in equation (1)
7*3/4-2=2Y
21/4-2=2Y
2Y=21/4-8/4
2Y=13/4
Y=(13/4)/2
Y=13/4*1/2
Y=13/8

so solution (x,y)=(3/4,13/8)

Answer 4

ok i got one last one.

8x = 2y + 5
3x = y + 7
Solve the system of equations by substitution.


(-9/2, -41/2)
(-1, -9/2)
no solution
coincident

Answer 5

8x = 2y + 5----(1)
3x = y + 7----(2)

in equation (2)
Y=3X-7

put in equation (1)
8X=2(3X-7)+5
8X=6X-14+5
8X-6X=-9
2X=-9
X=-9/2
X=-4.5

put the value of x in equation (1)
8*-4.5=2Y+5
-36=2Y+5
2Y=-36-5
2Y=-41
Y=-41/2
Y=-20.5

so solution (x,y)=(-4.5,-20.5)

Answer 6

ok but the last answer does not match any of my options here they are.

a.(-9/2, -41/2)
b.(-1, -9/2)
c.no solution
d.coincident

Answer 7

no solution