The standard form of the equation of a parabola is y=-2x-8x-13. what is the vertex form of the equation?

Presuming you mean y = -2x^2 - 8x - 13

Firstly, put the x terms in parentheses and factor out -2:

Next, we want to make what's inside those parentheses a perfect square. To do this, divide the x coefficient by 2 and square that result. In this case, that result is 4. Add 4 to the inside of the parentheses, and add 8 to the outside of the parentheses to balance it out. (Since when foiled, 4 x -2 = -8)

Next, factor what's inside the parentheses, and your final answer will be

to find the perimeter of the rectangle this is the expression:

x-9+x-9+3x-4+3x-4=138

if we simplify it:

8x-26=138

remember, 138 is what it all adds up to

the length is 11.5cm

the width is 57.5cm

the area is 661.25cm^2

the answers might not be correct use at own risk