Why is the middle term 2ab in (a+b)^2 and -2ab in (a-b)^2 when written in standard form

Step-by-step explanation:

You can try to expand, then you will get the middle term as 2ab or -2ab:

(a+b)² = (a+b)(a+b)

= a² + ab + ab + b²

= a² + 2ab + b²

As for the (a-b)², it will come in the same way :

(a-b)² = (a-b)(a-b)

= a² - ab - ab + b²

= a² - 2ab + b²

(Hope you can understand)

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

the answer is 844

step-by-step explanation:

it is 844 because if you add 836.50 + 7.5 you will get 844