Mae sells newspaper subscriptions door-to-door. In addition to a fixed salary, she earns a commission for each subscription that she sells. The table shows Mae’s total earnings, y (in dollars), from selling x newspaper subscriptions: Subscriptions Sold and Earnings Subscriptions Sold (x) Total Earnings (y) 1 135 2 145 3 155 Which equation best shows the relationship between x and y?

We don’t really need the choices here, but here they are just in case y = 10x + 125 y = x + 135 y = 10x + 135 y = x + 10

Recall that a generic linear equation is y = mx + b where m is the slope and b is the y-intercept. The slope, m, is also the rate of change for the y values. So look at the table, when x increases by 1, how much does y change? That’s your m-value. For your b-value, what would the y value be when x = 0? You can work from x = 1, y = 135 and subtract the rate of change to get the y value at x = 0. That ends up being your b-value. Once you have m and b, plug them into y = mx + b to get your final equation.

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