Which expression can be used to find the surface area of the following square pyramid?

Step-by-step explanation:

expression for surface area = a² + a √(a²/4+h²)

=4² + 2(4) √(4²/4+5²)

=16 + 8  √(16/29)

= 24 √0.55

= 20.65

-6 is the correct option from the above given options

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18