I need this to be explained

Step-by-step explanation:

So, the perimeter of a square means the total length or the sum of it's lenghts(four equal lengths )which means the formula for the perimeter is 4*l where l is a lenght

The area means the total area inside the square so jut imagine taking the length as a line, copy pasting it till the square turns black, that's the area.

The formula for the area is l*l which means a length multiplied by itself as I said above.

Calculate the answers by yourself.

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

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.