QUESTION IMAGE
Question
- by inspecting the graph, what can you determine about the solution(s) of this system?
20y = 15x + 55
12y = 9x + 33
Step1: Analyze the equations' slopes
First, rewrite both equations in slope - intercept form (\(y = mx + b\), where \(m\) is the slope and \(b\) is the y - intercept).
For the equation \(20y=15x + 55\), divide both sides by 20:
\(y=\frac{15}{20}x+\frac{55}{20}=\frac{3}{4}x+\frac{11}{4}\)
The slope \(m_1=\frac{3}{4}\)
For the equation \(12y = 9x+33\), divide both sides by 12:
\(y=\frac{9}{12}x+\frac{33}{12}=\frac{3}{4}x+\frac{11}{4}\)
The slope \(m_2 = \frac{3}{4}\)
Step2: Analyze the y - intercepts
From the slope - intercept form of the first equation \(y=\frac{3}{4}x+\frac{11}{4}\), the y - intercept \(b_1=\frac{11}{4} = 2.75\)
From the slope - intercept form of the second equation \(y=\frac{3}{4}x+\frac{11}{4}\), the y - intercept \(b_2=\frac{11}{4}=2.75\)
Since the two lines have the same slope (\(m_1 = m_2=\frac{3}{4}\)) and the same y - intercept (\(b_1=b_2=\frac{11}{4}\)), the two lines are coincident (they lie on top of each other).
Step3: Determine the number of solutions
When two lines are coincident, every point on one line is also on the other line. So, the system of equations has infinitely many solutions.
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The system of equations \(20y = 15x + 55\) and \(12y=9x + 33\) has infinitely many solutions because the two lines represented by the equations are coincident (they have the same slope and the same y - intercept).