What is the x -intercept of the equation 7 x plus 3 y is equal to 21 ?

The x-intercept is where the graph crosses the x-axis, so the y-coordinate is 0. Substitute y = 0 into 7x + 3y = 21: 7x = 21, so x = 3. The x-intercept is (3, 0), which is choice A.

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