Given a rectangle with a length of 48 and a width of 6, which rectangle is similar?

a) rectangle with a length of 36 and a width of 3
b) rectangle with a length of 42 and a width of 6
c) rectangle with a length of 64 and a width of 8
d) rectangle with a length of 72 and a width of 12

The above answer is wrong, a similar polygon is something that has all proportional sided and congruent angles. 48/36 does not equal 6/3 so A is incorrect. The answer is C, as 48/64 = 6/8.

1/800 is the right answer

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81