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For what value of k, the system of equations 3x−ky−3=03x - ky - 3 = 0 and 2x−3y−4=02x - 3y - 4 = 0 has no solution?

Solution

✅ Correct Option: 4

A system of two linear equations has no solution when the lines are parallel. This occurs when the lines have equal slopes but different y-intercepts.


Converting the first equation 3x−ky−3=03x - ky - 3 = 0 to slope-intercept form:

ky=3x−3ky = 3x - 3

y=3kx−3ky = \frac{3}{k}x - \frac{3}{k}

The slope is 3k\frac{3}{k} and the y-intercept is −3k-\frac{3}{k}.


Converting the second equation 2x−3y−4=02x - 3y - 4 = 0 to slope-intercept form:

3y=2x−43y = 2x - 4

y=23x−43y = \frac{2}{3}x - \frac{4}{3}

The slope is 23\frac{2}{3} and the y-intercept is −43-\frac{4}{3}.


For the lines to be parallel, the slopes must be equal:

3k=23\frac{3}{k} = \frac{2}{3}

3×3=k×23 \times 3 = k \times 2

9=2k9 = 2k

k=92k = \frac{9}{2}


When k=92k = \frac{9}{2}, the y-intercepts are:

First equation: −39/2=−3×29=−23-\frac{3}{9/2} = -\frac{3 \times 2}{9} = -\frac{2}{3}

Second equation: −43-\frac{4}{3}

Since −23≠−43-\frac{2}{3} \neq -\frac{4}{3}, the lines are parallel with different y-intercepts, confirming no solution exists.

Therefore, k=92k = \frac{9}{2}.

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