Question

Review the following problem and answer the questions that follow.

1) What mistake did I make?

2) What suggestion would you give me to avoid making that same mistake in the future?

Answer 1

The answer is below

Explanation:

1) Adding both equations is not suppose to yield that result, the correct result from the addition is:

-3x + y = 8 (1)

+

-3x + y = -4 (2)

-6x + 2y = 4

2) The coefficient of x and the coefficient of y in the first equation is equal to the coefficient of x and the coefficient of y in the second equation. Since they have the same equation, then to perform elimination, both equation is supposed to be subtracted and not added. Hence:

-3x + y = 8 (1)

-

-3x + y = -4 (2)

0 + 0 = 12

0 = 12

The equation has no solution