Question

how would I get the answer to #1

Answer 1

as you might be known that the opposite sides of a rectangle are equal.

so,

the perimeter of a rectangle becomes
length + breadth + length + breadth
2 length + 2 breadth
2 (length + breadth)



apply the terms,

2 (3x +5 + 3x^2+ 6x -10)
= 2 ( 3x^2 +9x -5)
= 6x^2 + 18x -10 units.

Answer 2

1)
A = (3x^2 + 6x -10)(3x+5)
A = 9x^3 + 15x^2 + 18x^2 + 30x - 30x - 50
A = 9x^3 + 33x^2 - 50

P = 2((3x^2 + 6x -10 + 3x+5)
P = 2(3x^2 + 9x - 5)
P = 6x^2 + 18x - 10

answer
Area = 9x^3 + 33x^2 - 50
Perimeter = 6x^2 + 18x - 10