Question 1035766
We would write, using the formula for the slope
{{{m = a + 3 = (5a^2-3a^2)/((3a+4)-(2a+2))}}}
which simplifies to
{{{a + 3 = 2a^2 /(a+2)}}}
Multiply by a+2, we get
{{{a^2 + 5a + 6 = 2a^2}}}
Rearranging we get
{{{a^2 - 5a - 6 = 0}}}
{{{(a-6)(a+1) = 0}}}
and 
a = 6 or a = -1