DSQ: Calculating the slope of parallel lines - GMAT Quantitative

Card 1 of 28

0
Didn't Know
Knew It
0
1 of 2019 left
Question

Consider this system of equations:

Does this system has exactly one solution?

Statement 1: The lines representing the equations are parallel.

Statement 2:

Tap to reveal answer

Answer

The solution of a system of linear equations is the point at which their lines intersect; if they are parallel, then by definition, there is no such point, and the system has no solution.

If , then we can rewrite the second equation as

In slope-intercept form:

This line has a slope of . The other equation has a line with slope of also, as can be easily seen since it is already in slope-intercept form. Since both equations have lines with the same slope, they are either the same line or parallel lines; either way, the system does not have exactly one solution.

← Didn't Know|Knew It →