Solve the following mathematical problems based on the provided flow diagram and table.

The flow diagram shows an input $x$ is first multiplied by $-1$, then that result is multiplied by 3.
So, the output $y$ is given by the formula:

• For Input $x = 0$: $y = -3(0) = 0$
• For Input $x = 1$: $y = -3(1) = -3$
• For Input $x = 2$: $y = -3(2) = -6$ (Note: The table in the question shows -5 for input 2, but based on the flow diagram's operations, the correct output is -6.)
• For Input $x = 4$: $y = -3(4) = -12$
• For Input $x = 8$: $y = -3(8) = -24$
• For Input $x = n$: $y = -3n$

2.2.3 Describe, in words, the steps to follow to calculate the input value for the given output value of -21.

3.1 The following shapes are made using squares.

• Shape 1 has 5 squares.
• Shape 2 has 7 squares.
• Shape 3 has 9 squares.