Final answer:
The initial value of the function y + 3x = 21 is 21.
Step-by-step explanation:
To find the initial value of the function y + 3x = 21, we need to isolate
Start by subtracting 3x from both sides of the equation:
y + 3x - 3x = 21 - 3x
y = 21 - 3x
Now, the equation is in the form y = mx + b, where m is the slope and b is the initial value.
In this case, the slope is -3 and the initial value is 21.
Therefore, the initial value of the function is 21.