Answer:
when we have a function:
y = f(x)
Evaluating the function just means replace the independent variable (x) by a given number.
Then, for the first case we have:
y=5x-4
when x = 5
Here we just need to replace x by 5 in the equation for y.
y = 5*(5) - 4
y = 25 - 4 = 21
for the second case:
y= -2/5x+3/8
when x=1/3
We just need to replace x by 1/3 in the equation, we will get:
y = -2/(5*(1/3)) + 3/8
y = - 2*3/5 + 3/8 = - 6/5 + 3/8
Now we need to find a common multiple between 8 and 5, that common multiple is 8*5 = 40
Then we can rewrite:
y = - (6*8)/40 + (3*5)/40 = (-48 + 15)/40 = -33/40
Finally, for the third case:
Equation Given Value Function Solution
y=3x+1
when x=4
We just need to replace x by 4 in the equation, so we will get:
y = 3*4 + 1
y = 12 + 1 = 13