5. In the following equation, identify the x-intercepts in the graph y = 3x2 + 19x – 40. (2 points)

Question

5.	In the following equation, identify the x-intercepts in the graph y = 3x2 + 19x – 40. (2 points)

campbell_st · Answer

start by letting y = 0 then just factor the quadratic, or even use the general quadratic formula and solve

I'd factorise 

multiply 3 and - 40      = -120

find the factors of -120 that add to 19, the larger factor is positive try 24 and - 5

then write you solution as 

             (3x + 24)(3x - 5)
            ----------------       = 0
                         3

find a find a common factor in one binomial, and it will cancel with the denominator.

the the values that make each binomial zero will be the intercepts