Question

X+3y=7 2x+y=4 using substitution method

Answer 1

Step-by-step explanation:

Solve the first equation for x.

x + 3y = -7

x = -7 - 3y

Now substitute (-7 - 3y) in for x in the second equation.

2x + 4y = -4

2(-7 - 3y) + 4y = -4

Solve to find the value of y.

-14 - 6y + 4y = -4

-14 - 2y = -4

-2y = 10

y = -5

Finally, substitute -5 in for y in the original equation and solve for x.

x + 3y = -7

x + 3(-5) = -7

x + -15 = -7

x = 8

Solution: (x = 8, y = -5)

You can check this solution by substituting these values in for x and y in the second equation.

2x + 4y = -4

2(8) + 4(-5) = -4

16 + -20 = -4

-4 = -4

You can also check this solution by graphing the two equations and finding their point of intersection which you can find in the attachment.

Graph work: Notice that the point of intersection is (8, -5).

Hope it helps.

Answer 2

Answer:

x + 3y = 7 _______( i )

2x + y = 4 _____( ii )

by , substituting the equation ( ii ) we get ,

2x + y = 4

y = 4 - 2x _________( iii )

put the value of y [ equation ( ii ) ] in equation ( i )

x + 3 * ( 4 - 2x ) = 7

x + 12 - 6x = 7

-5x = 7 - 12

-5x = -5

x = 1. ✓

now , put the value of x in equation ( iii )

y = 4 - 2*1

y = 4 - 2

y = 2. ✓