Question 67900
Equation: {{{a^2+4a=45}}}
Steps:
1. Make it a trinomial and move the 45 over.
{{{a^2+4a-45}}}
2. Factor it.
To factor this, find two factors of 45 that add to get 4a.
Those factors would be 9 and -5.
So, factored, it would be:
{{{a+9)(a-5)}}}
3. Find the solutions.
When finding the solution of an equation like this, perform the same steps you use to find restrictions. 
E.g. set each monomial to equal 0.
{{{a+9=0}}} AND {{{a-5=0}}}
Solve each mini-equation.
The solutions are -9 and +5.

Try it out:
{{{-9^2+4(-9)-45=0?}}}
Yup.

How about:
{{{5^2+4(5)-45=0}}}
Yup.

So your solution set is:
{-9,5}.