Anyone know this one? Quick!

4(x – 5) + (3x + 15) – 5x

4(x-5)+(3x+15)-5x

4x-20+3x-20+15=0

collect like terms

4x-5x+3x-20+15=0

2x-5=0

2x÷2=5÷2

x=5÷2

answer: 19 is   2

step-by-step explanation: i just looked at your answer and wrote it down

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this