Im confusion? Could someone help me out.

20cm

Step-by-step explanation:

for the triangle:

Perimeter = 30cm

a + a + a = 30

3a = 30

hence a = 10cm

For the rectangle:

Perimeter = 30cm

a + a + b + b = 30

but a = 10cm

10 + 10 + b + b = 30

20 + 2b = 30

2b = 10

hence b = 5cm

Perimeter of square = b + b + b + b

= 5 + 5 + 5 + 5 = 20cm

a4 - 3a2 - 1

step-by-step explanation:

step   1   :

equation at the end of step   1   :

  ((a4) -   3a2) -   1

step   2   :

trying to factor by splitting the middle term

2.1     factoring   a4-3a2-1  

the first term is,   a4   its coefficient is   1 .

the middle term is,   -3a2   its coefficient is   -3 .

the last term, "the constant", is   -1  

you would have to sell 24 bracelets.

step-by-step explanation:

84/3.5 = 24