$$ \int\_{\theta}^{\theta+1} ny(y-\theta)^{n-1}dy = \int\_{\theta}^{\theta+1} n(y-\theta)^n d(y-\theta) + \int\_{\theta}^{\theta+1} n\theta(y-\theta)^{n-1}d(y-\theta)$$

Please explain this equation easily(no skipping steps.) as possible as you can.
Someone just explain to me with "It's just algebra." I know this is algebra. What i don't know is how this algebra make right side from left side.