Question

Diagram shows two perpendicular straight lines,OB and CBD,drawn on a Cartesian plane.

Answer 1

Answer: (a) y = -3x + 10

               $\bold{(b)\x=\bigg(\dfrac{10}{3},0\bigg)}$  

Step-by-step explanation:

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: $m=\dfrac{y_2-y_1}{x_2-x_1}$

(x₁, y₁) = (0, 0) and (x₂, y₂) = (3, 1)

$m=\dfrac{1-0}{3-0} = \dfrac{1}{3}$

Step 2: Find the slope of CD (opposite and reciprocal of OB)

$m = \dfrac{1}{3}\qquad m_\perp=-\bigg(\dfrac{3}{1}\bigg) = -3$

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      distributed -3 into (x - 3)

y      = -3x + 10    added 1 to both sides

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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

$\dfrac{10}{3}=x$    divided both sides by -3