Answer: (a) y = -3x + 10
<u>Step-by-step explanation:</u>
The slope of line CD is perpendicular to line OB, which means they have opposite and reciprocal slopes.
Step 1: Find the slope of OB using the formula: ![m=\dfrac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=m%3D%5Cdfrac%7By_2-y_1%7D%7Bx_2-x_1%7D)
(x₁, y₁) = (0, 0) and (x₂, y₂) = (3, 1)
![m=\dfrac{1-0}{3-0} = \dfrac{1}{3}](https://tex.z-dn.net/?f=m%3D%5Cdfrac%7B1-0%7D%7B3-0%7D%20%3D%20%5Cdfrac%7B1%7D%7B3%7D)
Step 2: Find the slope of CD (opposite and reciprocal of OB)
![m = \dfrac{1}{3}\qquad m_\perp=-\bigg(\dfrac{3}{1}\bigg) = -3](https://tex.z-dn.net/?f=m%20%3D%20%5Cdfrac%7B1%7D%7B3%7D%5Cqquad%20m_%5Cperp%3D-%5Cbigg%28%5Cdfrac%7B3%7D%7B1%7D%5Cbigg%29%20%3D%20-3)
Step 3: Input the perpendicular slope and the slope into the Point-Slope formula: y - y₁ = m(x - x₁)
(x₁, y₁) = (3, 1) because it is the point the line will pass through
y - 1 = -3(x - 3)
y - 1 = -3x + 9 <em>distributed -3 into (x - 3)</em>
y = -3x + 10 <em>added 1 to both sides</em>
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The x-intercept of DQ is the same x-intercept as CD. The x-intercept is when y = 0
y = -3x + 10
0 = -3x + 10
-10 = -3x subtracted 10 from both sides
<em>divided both sides by -3</em>