X cm 2 cm
В.
A
C
x cm
The area of square ABCD is 7 cm?.
Show that x2 + 4x = 3
2 cm
+
A
D
Look at pic

Step-by-step explanation:

x×x=x²

2×x=2x

2×x=2x

2×2=4

Add like terms to make the equation:

So:

f

step-by-step explanation:

f

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