100 brainliest if correct

write and simplify a polynomial expression for the surface area of each figure.

SA = 16x^2 +30x+6

Step-by-step explanation:

The surface area is given by

SA = 2 (lw + lh + wh)

The length is 2x, the width is (x+3) and the height is (2x+1)

SA = 2 ((2x)*(x+3) + (2x)*(2x+1) + (x+3) (2x+1))

We need to distribute

SA = 2 ((2x^2+6x) + (4x^2+2x) + (2x^2 +6x+x+3))

Combine like terms

SA = 2 (2x^2+ 4x^2+2x^2+6x+2x  +6x+x+3)

SA = 2 (8x^2+15x+3)

Multiply by 2

SA = 16x^2 +30x+6

Step-by-step explanation:

Surface area = sum of all six faces

=2(2x)(x+3) + 2(2x)(2x+1) + 2(x+3)(2x+1)

=4x^2+12x + 8x^2+4x + 4x^2+14x+6

=16x^2 + 30x + 6

answer: 4

step-by-step explanation:

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1