Express 3/(x+1) + 4x/(2x+5) as a single fraction.

Multiply both numerators and denominator by the opposite denominators to get 3(2x+5)/(2x+5)(x+1) and 4x(x+1)/(2x+5)(x+1). Now the denominators are both equal so we can combine into one fraction and add the numerators to get the final answer of: (4x^2+10x+15)/(x+1)(2x+5)