Question

Is (-1,7) a solution for the system of linear equations below? x + 2y = 13 and 3x - y

Answer 1

Answer:

x = -9/7, y = 50/7.

Step-by-step explanation:

x + 2y = 13 ---------(eqn 1)

3x - y = -11 -----------(eqn 2)

Let's solve simultaneously using elimination method by multiplying eqn 2 by 2 so as to eliminate y.

3x - y = - 11 -------( × 2)

It gives

6x - 2y = - 22 ---------- ( new eqn 2)

x + 2y = 13 -----------( eqn 1)

Now add eqn 1 and new eqn 2

6x + x -2y + 2y = -22 + 13

7x = -9

Divide both sides by 7

7x/7  = -9/7

x = -9/7

Put x = -9/7 into eqn 1

x + 2y = 13

-9/7 + 2y = 13

Add 9/7 to both sides

-9/7+9/7 + 2y = 13+9/7

2y = 100/7

Divide both sides by 2

2y/2 = 100/7 ÷ 2

y = 100/7 × 1/2

y = (100÷2)/7

y = 50/7

Therefore

x = -9/7, y = 50/7

(-9/7, 50/7)

Therefore (-1,7) is not the solution for both equations , it is not a solution for NEITHER equation.

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