Problem Solving

VJesus12 wrote:

Which of the following could be the equation of line m?

(A) 6y + 6x = 7
(B) 3y = -4x - 3
(C) 5y + 10 = -4x
(D) y = 2
(E) x = -2

First off, we can eliminate answer choice D, since y = 2 is the equation of a HORIZONTAL line, and the given line is NOT horizontal.
Next, we can eliminate answer choice E, since x = -2 is the equation of a VERTICAL line, and the given line is NOT vertical.

Now notice that line m has a POSITIVE y-intercept.
In other words, when x = 0, y is some positive number.

Take the remaining answer choices and replace x with 0, and then find the corresponding y-value.

(A) 6y + 6(0) = 7
Simplify: 6y = 7
Solve: y = 7/6.
Since y is positive, we can keep A

(B) 3y = -4(0) - 3
Simplify: 3y = -3
Solve: y = -1
Since y is negative, we'll ELIMINATE B

(C) 5y + 10 = -4(0)
Simplify: 5y + 10 = 0
Solve: y = -2
Since y is negative, we'll ELIMINATE D

By the process of elimination, the correct answer is A

Cheers,
Brent