# The function is given by the formula y = 3x + 18. Determine: A) what is the value of y at x = -2.5

**The function is given by the formula y = 3x + 18. Determine: A) what is the value of y at x = -2.5 B) at what value of x is the value of y -3 C) whether the graph of the function passes through point A (-5.3)**

A) To determine the value of the function, we substitute the value of the argument into the equation of the graph:

y = 3 * (-2.5) + 18,

y = -7.5 + 18,

y = 10.5.

Answer: The value of the function is 10.5.

B) Let’s calculate what the value of the argument is, if it is known that the function takes the value -3 using substitution:

-3 = 3x + 18,

3x = -21,

x = -7.

Answer: the argument has a value of -7.

C) Substitute x = -5 into the equation and determine what y is equal to:

3 * (-5) + 18 = 3.

y = 3, the value is equal to the ordinate of point A.

Answer: yes, the graph goes through point A.