Question

Solve this system of linear equations using substitution.

{(3x+2y=10),(2x+y=1):}
A (-8,17)
B(-4,17)
C(-8,6)
D (8,17)

Answer 1

A

Explanation:

3x + 2y = 10 → (1)

2x + y = 1 ( subtract 2x from both sides )

y = 1 - 2x → (2)

substitute y = 1 - 2x into (1)

3x + 2(1 - 2x) = 10

3x + 2 - 4x = 10

- x + 2 = 10 ( subtract 2 from both sides )

- x = 8 ( multiply both sides by - 1 )

x = - 8

substitute y = - 8 into (2)

y = 1 - 2(- 8) = 1 + 16 = 17

solution is (- 8, 17 )

Answer 2

`y = 1 - 2x.....(3) \\ \\ 3x + 2(1 - 2x) = 10 \\ 3x + 2 - 4x = 10 \\ 3x - 4x = 10 - 2 \\ - x = 8 \\ ( - x)/( - 1) = (8)/( - 1) \\ x = - 8 \\ \\ \\ y = 1 - 2( - 8) \\ y = 1 + 16 \\ y = 17`

NOTE I FIRST DERIVED THE THIRD EQUATION FROM THE SECOND EQUATION BY MAKING Y THE SUBJECT OF THE EQUATION AND SUBSTITUTED THE DERIVED EQUATION TO THE FIRST EQUATION BY PLUGGING IN 1-2x IN THE PLACE OF Y AND SOLVED SO ON.

(-8,17)

OPTION A IS THE ANSWER.

GOODLUCK