What is the x-intercept of the line with the equation 1/3x + y = - 15?

You find the x-intercept by replacing y with zero. 1/3x+0=-15. 1/3x=-15. Next, you have to divide each side by 1/3. In order to divide a fraction, you have to flip it, then multiply. That means you are now multiplying by 3. - 15 times 3 is - 45, which means x=-45. That means your answer is (-45,0)