Which equation is in standard form?

• A. Ax + By = C
• B. y = mx + b
• C. Ax + By ≤ C
• D. 3x + 2 = 7

Answer: (A)

Standard form for a linear equation in two variables is written as Ax + By = C, where A, B, and C are numbers (often integers) and the left side contains both x and y terms with the right side a single constant. It’s the exact equality form that places the x- and y-terms on one side and a constant on the other.

The given equation fits this structure because it has both x and y terms on the left and a single constant on the right, written as an exact equality.

The other forms aren’t standard two-variable equations in this sense: y = mx + b is the slope-intercept form, which expresses y directly as a function of x; Ax + By ≤ C is an inequality, not an equality; and 3x + 2 = 7, while an equality, lacks the y-term, so it doesn’t present the familiar two-variable standard form.