Final answer:
To find y when x = 45, we substitute 45 for x in the equation y = 9 + 3x, thus y equals 9 + 135 which simplifies to y = 144.
Step-by-step explanation:
To find the value of y when x = 45, we use the given linear equation y = 9 + 3x.
Since we are given that y = 8 when x = 3, this value does not affect our new calculation because we are looking for the value of y corresponding to a different x-value, which is 45 in this case.
Thus, we substitute x = 45 into the equation:
y = 9 + 3(45)
y = 9 + 135
y = 144
Therefore, when x = 45, the value of y is 144.