Math factorization

[Machinima]

I need the simplified of this question (√x - √y)^2 - (√x - √y)^2

choices:

A) 2√xy
b) 2(x-y)
c) 4√xy
d) √x - √y
e) √x + √y

I say its b but if it isn't I would like to know why

[Ad Bot]

[Pie Crust]

(√x - √y)*(√x - √y) + (√x + √y)*(√x + √y)
√x^2 - √xy - √xy + √y^2 + √x^2 + √xy + √xy + √y^2
x - 2√xy + y + x + 2√xy + y
2x + 2y

...wat

[otto-san]

are you sure you typed the problem correctly

[Machinima]

(√x - √y)*(√x - √y) + (√x + √y)*(√x + √y)
√x^2 - √xy - √xy + √y^2 + √x^2 + √xy + √xy + √y^2
x - 2√xy + y + x + 2√xy + y
2x + 2y

...wat

isn't this the same as 2(x-y)

[Pie Crust]

2(x+y)

[Machinima]

2(x+y)

well it could be a typo on my sheet but they tell you to mark the closest one so its b

[otto-san]

pie crust did defo copy what you had in the OP wrong tho

the problem you gave should evaluate to 0 i'm p sure

[Pie Crust]

pie crust did defo copy what you had in the OP wrong tho

English? (Or spanish)

[otto-san]

the problem wasn't
(√x - √y)*(√x - √y) + (√x + √y)*(√x + √y)

it was

(√x - √y)*(√x - √y) - (√x - √y)*(√x - √y)

[Pie Crust]

(√x - √y)*(√x - √y) - (√x - √y)*(√x - √y)
That - sign will invert all of the signs in the multiplication.

[otto-san]

no it won't

the problem says to take (√x - √y)^2 and subtract (√x - √y)^2, which is zero. p sure op must have copied the problem wrong

[Steve5451²]

i failed math

[Pie Crust]

no it won't

I'm pretty sure it will.

OP: Stick to B.

[Racerboy]

I'm pretty sure it will.

OP: Stick to B.

It will, but you did it wrong. You have to distribute the negative to every term, thus making the operation inside the parenthesis minus but switching the places of the root(x) and root(y). I'm on my phone now otherwise I'd do it.

[otto-san]

if the problem only said -(√x - √y), you're right, because that says -1 * (√x - √y), which is (-√x + √y).

but it's -(√x - √y)², which evaluates to -(x - 2√xy + y), or (-x + 2√xy - y).