##### Quadratic eq. and graphs - WAS...

###### The graph of the curve y = 2x^{2} - x -1 and a straight line PQ were drawn to solve the equation 2x^{2} - 5x+2 =0. What is the equation of the line PQ?

y = 2x-3

y=4x+1

y=3x-3

y=4x-3

Correct Answer

Incorrect Answer

How to get the right answer:

Let the straight line be px+qAccording to the question, the solution of the curve 2x^{2} - 5x+2 = 0 is when y = 2x^{2} - x - 1 = px+q

Rearrange this

By comparing this expression to 2x^{2} - 5x+2 = 0, we can write

and

Therefore the equation of line PQ is