Mathematics

Mathematics

Problem

In the equation y−y1=m(x−x1)y - y_1 = m(x - x_1) of a straight line, write an expression for the yy-intercept when the same line is expressed in the form y=mx+cy = mx + c.
Intuitive explanation

The key insight is that both forms describe the same line, so you can convert between them algebraically. Start with point-slope form y−y1=m(x−x1)y - y_1 = m(x - x_1), expand it, and rearrange to isolate yy on one side—this reveals cc as the constant term that emerges. The yy-intercept is simply what you get when you solve for the constant in slope-intercept form.

Intuitive explanation

The key insight is that both forms describe the same line, so you can convert between them algebraically. Start with point-slope form y−y1=m(x−x1)y - y_1 = m(x - x_1), expand it, and rearrange to isolate yy on one side—this reveals cc as the constant term that emerges. The yy-intercept is simply what you get when you solve for the constant in slope-intercept form.

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