Question

Maya maintains the gardens in the city parks. In the summer, she plans to build a walkway through the rose garden. The area of the walkway, A, in square metres, is given by A=60x+2x^2, where x is the width of the walkway in metres. If the area of the walkway must be 800 m^2, determine the width.

Answer 1

@cerezas

Answer 2

ok well you have 800 = 2x^2 + 60x
first make that equal to 0

Answer 3

okay

Answer 4

so 0= 2x^2+60x-800

Answer 5

ok so now you can factor this

Answer 6

2(x^2+30x-200)

Answer 7

alright but then you want to factor the quadratic part
so find two number that multiply out to -800X2 = -1600 and add up to 60

Answer 8

I'm lost now :S

Answer 9

do you remember how to factor quadratic equations?

Answer 10

I think so, I wish i had my notes with me

Answer 11

ill go look online, they are posted on her website

Answer 12

I think I got it

Answer 13

awesome, so can you factor it or do you want me to guide you?

Answer 14

2(x+10)(x-20)

Answer 15

or is that totally wrong,

Answer 16

can you guide me :P?

Answer 17

yeah sure
so do what i said before and find two numbers that multiply to -1600 but add to 60

Answer 18

okay so I'm going to use the product and sum method

Answer 19

^that's what i'm talking about

Answer 20

So am I using the equation 2x^2+60x-800

Answer 21

or what, I'm lost on that part

Answer 22

okay that's right

Answer 23

how come it isn't adding to -800, i forget

Answer 24

it has to add to 60

Answer 25

and the product must be a*c which is 2*-800 = -1600