What is the factored form of x2 - 12x - 45?

(x - 15)(x + 3)

Step-by-step explanation:

Factors of 45 include 5 and 9, 3 and 15, 1 and 45, and so on.

Note that 3*15 =+45; this is not what we wanted.  Thus, try (-3)*15 = -45.

Do -3 and 15 combine to yield -12?  No.  Thus drop (-3)(15) and try (3)(-15).

Do 3 and -15 combine to yield -12?  YES

Therefore, the factored form of x² - 12x - 45 is (x - 15)(x + 3).

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6