Linear Algebra Basics: Systems. Game on.

Linear Algebra Basics: Systems is a grade 8 math skill aligned to Common Core standard 8.EE.C.8.b. Below are 8 practice questions with answers and step-by-step explanations, drawn from the 10 linear algebra basics: systems problems our math games drill.

CCSS 8.EE.C.8.b10 questions in the bank
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Warm-upeasy

{2x+y=7x−y=2\begin{cases} 2x + y = 7 \\ x - y = 2 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=−2x+7y = -2x + 7 and y=x−2y = x - 2. The slopes −2-2 and 11 are different, so the lines intersect at exactly one point.

Mid-gameeasy

{5x−3y=42x+y=7\begin{cases} 5x - 3y = 4 \\ 2x + y = 7 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=53x−43y = \dfrac{5}{3}x - \dfrac{4}{3} and y=−2x+7y = -2x + 7. The slopes 53\dfrac{5}{3} and −2-2 are different, so the lines intersect at exactly one point.

Mid-gameeasy

{5x−10y=15x−2y=4\begin{cases} 5x - 10y = 15 \\ x - 2y = 4 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=12x−32y = \dfrac{1}{2}x - \dfrac{3}{2} and y=12x−2y = \dfrac{1}{2}x - 2. The slopes are the same, but the yy-intercepts differ, so the lines are parallel and the system has zero solutions.

Mid-gameeasy

{x+3y=42x+6y=8\begin{cases} x + 3y = 4 \\ 2x + 6y = 8 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=−13x+43y = -\dfrac{1}{3}x + \dfrac{4}{3} and y=−13x+43y = -\dfrac{1}{3}x + \dfrac{4}{3}. The slopes and yy-intercepts match, so the equations describe the same line and the system has infinitely many solutions.

Mid-gameeasy

{3x+4y=10x−2y=1\begin{cases} 3x + 4y = 10 \\ x - 2y = 1 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=−34x+52y = -\dfrac{3}{4}x + \dfrac{5}{2} and y=12x−12y = \dfrac{1}{2}x - \dfrac{1}{2}. The slopes −34-\dfrac{3}{4} and 12\dfrac{1}{2} are different, so the lines intersect at exactly one point.

Mid-gameeasy

{6x+9y=122x+3y=7\begin{cases} 6x + 9y = 12 \\ 2x + 3y = 7 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=−23x+43y = -\dfrac{2}{3}x + \dfrac{4}{3} and y=−23x+73y = -\dfrac{2}{3}x + \dfrac{7}{3}. The slopes are the same, but the yy-intercepts differ, so the lines are parallel and the system has zero solutions.

Mid-gameeasy

{4x−2y=68x−4y=12\begin{cases} 4x - 2y = 6 \\ 8x - 4y = 12 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=2x−3y = 2x - 3 and y=2x−3y = 2x - 3. The slopes and yy-intercepts match, so the equations describe the same line and the system has infinitely many solutions.

Buzzer beatereasy

{x+y=53x−y=3\begin{cases} x + y = 5 \\ 3x - y = 3 \end{cases}

How many solutions does the given system of equations have?

Rewrite in slope-intercept form: y=−x+5y = -x + 5 and y=3x−3y = 3x - 3. The slopes −1-1 and 33 are different, so the lines intersect at exactly one point.

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