Which equation represents a parabola opening to the left with a vertex at the origin and a focus at (-7, 0)?

a. x=1/28 y^2
b. x= - 1/28 y^2
c. y= 1/20 x^s
d. y= - 1/20 x^s

Step-by-step explanation:

the standard equation,

                       ---(1)    , when opening towards left or right

                      focus at (a , 0)

                      ---(2)      , when opening towards top or bottom

                      focus at (0,  a)

if a is negative parabola will open toward negative axes ( down or left) and vice versa.

re- arranging option b. we get

                        -----(3)

therefore, a =  -7

(3) is similar to (1)

So it is facing left with focus at (-7,0)

step-by-step explanation: