Answer:
y = -3x + 12
Step-by-step explanation:
<u><em>Very similar to the other question i answered, by here's a step by step anyway in case you find it helpful : )</em></u>
There are lots of different methods to do these types of questions, but this is the way i like to do it.
Coordinate (x1, y1) : (1, 9) and Gradient (m): -3
Start with this generic equation:
y- y1 = m(x-x1)
Substitute in the values they have given you:
y - (9) = -3(x-1)
This becomes:
y -9 = -3x +3
Keep solving by moving the 10 over to the other side:
y = -3x + 3 +9
y = -3x + 12
An easy way to double check:
1) the coefficient of x is the slope. We got -3x, and the slope is -3, so that's correct.
2) Substitute x=1 into the equation, and we get 9, which is the exact coordinate that they gave us. This is also right.
Hope this helped : )
