3x (7+(-3)^2)÷3 i'm confused with the steps

I believe the order of operations would be this:

-3(7+9)/3

-3(16)/3

-16

You should use the acronym BODMAS which is Bracket, Of, Division, Multiplication, Addition and Subtraction
work out what is in the brackets first
because the 3 is negative in front of the -3 squared because negative (a negative and a positive makes a negative )
any number decided by itself equals 1
therefore the -3 at the beginning if the sum is divided by the three at the end of the sum
then evaluate the powers
the 3 squared becomes 9
lastly calculate what's inside the brackets and multiply

your working should look like this :

-3 (7+(-3)^2)÷3
-1(7-3^2)
-1 (7-9)
-1 (-2)
=2

Or like this:

-3(7−9)÷3
-3×−2÷3
6÷3
=2

. So the slope is 3 which you can plug in one of the points and get the final equation which is :