Question

solve for the value of d.

Explanation:

Step1: Set up the equation

Since the sum of the two angles and the right - angle (\(90^{\circ}\)) is \(180^{\circ}\) (a straight line), we have \((6d + 7)+(9d-7)+90 = 180\).
Simplify the left - hand side: \((6d+9d)+(7 - 7)+90=180\), which becomes \(15d+90 = 180\).

Step2: Solve for \(d\)

Subtract \(90\) from both sides: \(15d+90-90=180 - 90\), so \(15d=90\).
Divide both sides by \(15\): \(d=\frac{90}{15}\).

Answer:

\(d = 6\)