A triangle has side lengths of (9d+ 4) centimeters, (9d + 2) centimeters, and (3f - 2) centimeters. Which expression represents the perimeter, in centimeters, of the triangle?

Perimeter is the sum of the 3 sides.

Add the 3 sides together by combining like terms.

9d +4 + 9d+2 + 3f -2

9d+9d = 18d

4 + 2-2 = 4

Combining like terms you get:

18d +3f +4

step-by-step explanation:

6.48/4 4 goes into 6.48 1.62 times

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15