How do I find the slope, domain, range and y intercept of y=-2x

Slope is defined as the rate of change, in this case the change in y with respect to x. In standard form for a binomial linear equation, y = mx + b. The constants m and b are the slope and intercept, respectively. For your equation, the slope is - 2 and the intercept is 0. The domain (possible values of x) for this graph is (-∞, ∞) and the range (possible values of y) is also (-∞, ∞).