c) ∫(x + 4)/(x² + 8x - 9)dx

c) ∫(x + 4)/(x² + 8x - 9)dx
Answer
Explanation:
Step1: Let (u = x^{2}+8x - 9)
Differentiate (u) with respect to (x): (du=(2x + 8)dx=2(x + 4)dx), so ((x + 4)dx=\frac{1}{2}du)
Step2: Substitute into the integral
The integral (\int\frac{x + 4}{x^{2}+8x - 9}dx) becomes (\int\frac{\frac{1}{2}du}{u}=\frac{1}{2}\int\frac{du}{u})
Step3: Integrate (\frac{1}{u})
We know that (\int\frac{du}{u}=\ln|u|+C)
Step4: Substitute (u) back
Substituting (u=x^{2}+8x - 9) back, we get (\frac{1}{2}\ln|x^{2}+8x - 9|+C)
Answer:
(\frac{1}{2}\ln|x^{2}+8x - 9|+C)