When it says "when x = 7" this instantly means you should evaluate.
You are going to plug in the number "7", which means the variable "x" is going to become "7":
[tex]7.5(3x+4)[/tex]
[tex]7.5((3)(7)+4)
[/tex]
So, now what you're going to do is MULTIPLY 3 and 7:
(Note: Remember PEMDAS, work in the Parenthesis first)
[tex]3*7=21[/tex]
So, now your problem should look like this:
[tex]7.5(21 + 4)[/tex]
Next step is to add 21 and 4, (We are still working in Parenthesis):
[tex]21+4=25[/tex]
Final step, you are going to Multiply 7.5 and 25 to get your answer, like this:
[tex]7.5*25=187.5[/tex]
Your correct answer is:
[tex]187.5[/tex]
Good luck with your studies, I hope this helps~!
