Identify integral: Identify the integral to be solved.We have the integral:∫3x+56x2dxWe need to find a way to simplify this integral to make it easier to solve.
Use substitution: Use substitution to simplify the integral.Let u=3x+5. Then, dxdu=3, or du=3dx. We need to express x2 and dx in terms of u and du.
Solve for x: Solve for x in terms of u.Since u=3x+5, we have x=3u−5. Now we can find x2 in terms of u.x2=(3u−5)2
Substitute x2 and dx: Substitute x2 and dx in the integral.x2=(3u−5)2dx=3duNow, substitute these into the integral:∫u6(3u−5)2⋅(3du)
Simplify the integral: Simplify the integral. ∫u6(3u−5)2⋅3du= ∫96(u2−10u+25)u1⋅3du= ∫92(u2−10u+25)u1⋅du= 92∫uu2−10u+25du
Split into integrals: Split the integral into three separate integrals.(92)∫(u2−10u+25)/(u)du= (92)(∫u23du)−10∫u21du+25∫u−21du)
Integrate each term: Integrate each term separately.∫u23du=52u25+C1∫u21du=32u23+C2∫u−21du=2u21+C3
Combine integrals: Combine the integrals and multiply by the constant.(92)((52)u25−10(32)u23+25(2)u21)+C= (92)((54)u25−(320)u23+50u21)+C= (458)u25−(2740)u23+(9100)u21+C
Substitute back for u: Substitute back for u to get the integral in terms of x.u=3x+5458(3x+5)25−2740(3x+5)23+9100(3x+5)21+C
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