Question

Thank youuuuuuuuuuuuuu

Answer 1

The perimeter, as you already know, is the sum of all the sides.

14)

$\bf (x+3)+(2x+4)+(y)=\stackrel{perimeter}{6x}\implies 3x+7+y=6x \\\\\\ 7+y=3x\implies y=3x-1$

15)

a rectangle has twin widths and twin lengths, therefore

$\bf \stackrel{width}{(3x-3)}+\stackrel{width}{(3x-3)}+\stackrel{length}{(y)}+\stackrel{length}{(y)}=\stackrel{perimeter}{10x+6} \\\\\\ 6x-6+2y=10x+6\implies -6+2y=4x+6\implies 2y=4x+12 \\\\\\ y=\cfrac{4x+12}{2}\implies y=\cfrac{4x}{2}+\cfrac{12}{2}\implies y=2x+6$