Use substitution to Solve:?

Question

(1) x = 3y - 2
2x + 4y = 16

(2) 2x + y = 7
5x - 2y = 4

Answer 1

Question 1
2(3y - 2) + 4y = 16
6y - 4 + 4y = 16
10y = 20
y = 2
x = 6 - 2
x = 4
Solution
x = 4 , y = 2

Question 2
5x - 2(7 - 2x) = 4
5x - 14 + 4x = 4
9x = 18
x = 2
4 + y = 7
y = 3
Solution
x = 2 , y = 3

Answer 2

(1)
since the first formula is in the terms of x, substitute the value of x on the second formula with the first one.
x = 3y - 2
then,
2x + 4y = 16
2 (3y - 2) + 4y = 16
6y - 4 + 4y = 16
10y = 16 +4
10 y = 20
y = 2
so x = 3(2) - 2 = 6 - 2 = 4

(2)
2x + y = 7
________-2x
y = 7 - 2x
then.
5x - 2y = 4
5x - 2 (7 - 2x) = 4
5x - 14 + 4x = 4
9x = 18
x = 2
so y = 7 - 2(2) = 7 - 4 = 3

Answer 3

1) substitute 3y-2 in for the x in the second equation
2(3y-2) +4y=16 and then solve.
6y-4+4y=16 simplify 10y-4=16....... 10y=20
so y=2
then you put y into the equation
x= 3(2) -2 = 4

2) in this one you must solve the first equation for y.
y= 7-2x
5x-2(7-2x)=4
5x-14+4x=4
9x=18
x=2
y=7-2(2)
y=3

don't forget to check

Answer 4

x = 3y -2 so
substitute 3y-2 in the formula for x and solve for y first

2x + 4y = 16 (original formula)
2(3y-2) + 4y = 16 (express the formula by reducing to just y)
6y - 4 + 4y = 16 (simplify by doing the multiplication)
6y + 4y = 20 (Add 4 to both sides to simplify the left
10y = 20 (Simplify again by adding the 6y and 4 y
y = 2 (Divide both sides by 10 to simplify
x = 3(2) - 2
x = 4 (substitute the now known value for y
2(4) + 4(2) = 16 Test your answer and it is true
y=2 x =4

Answer 5

x=3y-2
2x+4y=16
2(3y-2)+4y=16 .....(Putting the value of x in 2x+4y=16)
6y-4+4y=16
6y+4y=16+4
10y=20
y=20/10
y=2

2) 2x+y=7
y=7-2x

Since 5x-2y=4
therefore 5x-2(7-2x)=4......(Putting the value of y)
5x-14+4x=4
9x-14=4
9x=4+14
9x=18
x=18/9
x=2

Hope U understand.

Answer 6

2(3y-2)+4y-16=0
6y-4+4y-16=0
10y=20
y=2
x=3*2-2
x=4

2. y=7-2x

5x-2(7-2x)=4
5x-14+4x=4
9x=18
x=2
y=7-2*2
y=3