
area using integrals
Hi, the problem starts out by giving:
y = 2+x1 and y = (1/5)x+7
the next step in the solution book takes y = 2+x1 and turns it into:
3x, x<= 1
1+x, x >=1
I know that 3x is negative and 1+x is positive but how do you figure that out?
Thank you

What are you to do exactly. Are you given limits of integration?.
Break the abs up into two separate integrals.
$\displaystyle \int_{\frac{15}{2}}^{1}[(\frac{1}{5}x+7)(x+1)]dx+\int_{1}^{\frac{10}{3}}[(\frac{1}{5}x+7)(x+3)]dx$
EDIT: Oops, looks like I mistakenly used 2+x+1 instead of 2+x1. You get the idea. Adjust accordingly.