Question

If x is a whole number and 437 = (21 + x)(21 - x), then x =

Answer 1

437 = (21 + x)(21 - x)

-x^2 +441 = 437
-x^2 +878 = 0

a=-1 b=0 c=878
Putting this into quadratic formula:

x= 0 +- square root (0 -4*-1*878)/2*-1

x= +- square root ( -4*-1*878)/-2
x = +-square root (3,512) / -2
x = +-square root (878)
x = +29.6310647801
x = -29.6310647801

Answer 2

441 - 4 = 437 (Difference of 2 squares)
441 - 4 = (21 + 2) * (21 - 2) = 437

What is the value of x? @kbriones0

Answer 3

437?

Answer 4

kbriones0, the value of x has already been posted by me
I used the quadratic formula
(scroll back just a bit)

Answer 5

I got the value of x as being 2.

@wolf1728 I am not following how the answer of x = +29.6310647801 x = -29.6310647801 was derived.

Answer 6

@wolf1728 >> x is a whole number

Answer 7

I made a mistake in my previous answer:
437 = (21 + x)(21 - x)

-x^2 +441 = 437

That becomes
-x^2 = -4

x^2 -4 = 0

(x+2)*(x-2) =0

x = 2
x = -2