Solve a) x^2+7x-10=0

Write



as



and compare it to



and notice that , , and 

Then substitute in the quadratic formula

 

and get

 

Then simplify:

 

 

which is really two answers:

 and 


b)find the x intercepts of f(x)=x^2+7x-10

 They are the points:

 and 

They are the points marked P and Q below on the graph of  




If you get the decimal approximations with a calculator,
you'll find that P is approximately the point P(-8.2,0) and
Q is approximately the point Q(1.2,0)

Edwin