First, this is your current equation: y= -3x+b. Fill in one of your coordinates into the equation (it doesn't matter which one because they're both the same). It should look like this: 3 = -3(1) + b. Multiply -3 and 1 to get -3. So, this is what it should look like: 3 = -3 + b. Add 3 to both sides to get your y-intercept of 6. Go back to your original equation and plug in 6 to b. This is your final equation: y = -3x + 6. Hope this helped!
