Isolate square root terms: First, we need to isolate the square root terms on one side of the equation. We can do this by subtracting 4 from both sides of the equation.9d+4−4=5d−49d=5d−4
Square both sides: Next, we square both sides of the equation to eliminate the square roots.(9d)2=(5d−4)29d=(5d−4)(5d−4)
Expand using FOIL method: Now we need to expand the right side of the equation using the FOIL method (First, Outer, Inner, Last).9d=(5d)(5d)−4(5d)−4(5d)+169d=5d−85d+16
Isolate square root term: We then isolate the term with the square root on one side of the equation by moving all other terms to the opposite side.9d−5d=−85d+164d=−85d+16
Move constant term: Next, we move the constant term to the other side by subtracting 16 from both sides.4d−16=−85d
Divide by −8: Now we divide both sides by −8 to isolate 5d.(4d−16)/−8=5d−0.5d+2=5d
Square both sides: We square both sides again to eliminate the square root.(−0.5d+2)2=(5d)20.25d2−2d+4=5d
Set equation to zero: We bring all terms to one side to set the equation to zero and solve for d.0.25d2−2d+4−5d=00.25d2−7d+4=0
Correct previous step: This is a quadratic equation, and we can solve it by using the quadratic formula, d=2a−b±b2−4ac, where a=0.25, b=−7, and c=4. However, we made a mistake in the previous step. The correct equation after squaring both sides should be: 0.25d2−2d+4=5d0.25d2−7d+4=0 This is incorrect because the term −2d should have been −1d when we multiplied −0.5d by −2. Let's correct this. a=0.250a=0.251