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Solve this system of equations by using an algebraic method.

Equation:
y = 3x + 5
3x - y = 5

User BooRanger
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1 Answer

3 votes

Answer:

Explanation:

Substitute our first equation into the second equation. We are given y, so this is ideal of substitution method.

y = 3x + 5
3x - y = 5

3x - (3x + 5) = 5
3x - 3x - 5 = 5
-5 = 5

There is no solution for the system because after solving, the sides of the equation are not equal. We can further check this by writing the second equation in a "y = mx + b form, or slope-intercept form. This well tell use about the graphs of the equations.

3x - y = 5
-y = -3x + 5

y = 3x -5

When comparing with the first equation, we can see that the slope is 3 for both lines, but the y-intercept is different. This means we have two parallel lines that cross the y-axis at (0, 5) and (0, -5). From this, one can conclude there is no solution because parallel lines with different y-intercepts will never cross.

User Linsek
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