How can a straight line be expressed in algebraic form?

A straight line can be expressed in algebraic form using the slope-intercept equation, which is represented by the formula y = mx + b. In this equation, 'm' denotes the slope of the line, indicating how steep the line is, while 'b' represents the y-intercept, the point where the line crosses the y-axis.

This formula is fundamental in coordinate geometry as it clearly establishes the relationship between the variables x and y for any straight line.

The other choices present variations that misunderstand or misrepresent the essential attributes of a linear equation. For instance, the option that uses 'c' instead of 'b' fails to align with the standard format for a line equation. The option depicting 'ax² + bx + c' refers to a quadratic equation rather than a linear one and represents a parabolic graph, which is inherently different. Lastly, the variation that uses 'm' again instead of a constant term for the y-intercept is not a standard or meaningful representation of a straight line.

Thus, y = mx + b is the universally accepted format for expressing a straight line in algebraic form, accurately conveying both its slope and intercept characteristics.