Two lines L1 and L2 pass through the point of intersection of 2y=x-13 and 3y+x+12=0. L1 passes through P(-4,-7) and L2 is perpendicular to 2x-5y=4.find the acute angle between L1 andL2

Cherie works in retail and her weekly salary includes commission for the amount she sells. the equation s=400+0.15c models the relation between her weekly salary, s, in dollars and the amount of her sales, c, in dollars. interpret the slope of the equation.