Q. Find the x-intercept of the line \(10x + 14y = -18\).
Answer
Set \(y=0:\ 10x+14\cdot0=-18\). So \(10x=-18\), hence \(x=-\tfrac{9}{5}=-1.8\). The x-intercept is \(\left(-\tfrac{9}{5},0\right)\).
Detailed Explanation
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Understand what the x-intercept means.
The x-intercept is the point where the graph of the line crosses the x-axis. Every point on the x-axis has y = 0, so to find the x-intercept we set y equal to 0 in the equation of the line.
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Substitute y = 0 into the given equation.
The line is given by
\[10x + 14y = -18\]
Set y = 0 and substitute:
\[10x + 14(0) = -18\]
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Simplify the equation after substitution.
Because 14(0) = 0, the equation becomes
\[10x = -18\]
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Solve for x.
Divide both sides of the equation by 10 to isolate x:
\[x = \frac{-18}{10}\]
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Simplify the fraction and (optionally) convert to a decimal.
Reduce the fraction by dividing numerator and denominator by 2:
\[x = \frac{-9}{5}\]
As a decimal, this is
\[x = -1.8\]
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State the x-intercept as a point.
The x-intercept is the point on the x-axis corresponding to this x-value, so the x-intercept is
\[\left(-\frac{9}{5},\,0\right)\quad\text{(which is the same as }\left(-1.8,\,0\right)\text{)}.
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Quick check (verification).
Substitute x = -9/5 and y = 0 back into the original equation:
\[10\left(-\frac{9}{5}\right) + 14(0) = 10\cdot\left(-\frac{9}{5}\right) = -18,\]
which matches the right-hand side, confirming the result is correct.
Graph
FAQs
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