Write the equation of the directrix of the parabola shown below. Write your answer without using spaces. y^2 - 4x + 4y - 4= 0

y = - 3

Step-by-step explanation:

The general form of the equation of a parabola is given by:

with foci (h,k) and directrix equation given by y = k - p.

The parabola equation that you have is

you complete squares to get the general form of the equation:

Next, you compare the last expression with the general for of the equation of a parabola and you obtain:

hence, the directrix equation is y = k - p = - 2 - 1 = - 3

1/2*qr*rs

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4