I dont what is the perimeter?​

20.4 ?

Step-by-step explanation:

Formula is P=2L+2W so 7(2) + 3.2 (2) = 20.4

20.4 inches

Step-by-step explanation:

(7x2) + (3.2x2) = 20.4

Have a great day <3

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

i think its a and d

step-by-step explanation: