Question

y = 3x - 4
x = 9

A. (9, 23)
B. (1, -1)
C. (0, -4)
D. (9, 31).
How do I solve this?

Answer 1

Let's read the problem. Ok so they give us y= 3x-4 and x= 9. What we want to do is use direct substitution. The best way of doing this would to just take the 9 from x= 9 and plug it right into our y= equation (we want to find the y coordinate in order to get the ordered pair).
Using direct substation we will get: y= 3(9)-4
Simplify!
y= 27-4
y= 23
Now that we have our y we are done! Just take the x that we already know and make the ordered pair. (9,23)
So the answer is is A.