Rahul simplified an expression. his work is shown below.
7(8.5-1.5)+8divided by2
step 1. 7(7)+8 divided by 2
step 2. 49+8 divided 2
step 3. 57 divided by 2
step 4. 28.5
where did rahul make his first mistake?

Step 3

Step-by-step explanation:

He should have divided 8 by 2 and then added it to 49.

step 3

Step-by-step explanation:

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