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# Writing Linear Equations in Point-Slope Form **WHAT IS POINT-SLOPE FORM?** 1. Point-slope form of a linear equation is $y - y_{1} = m(x - x_{1})$. It is called point-slope form because it you just need the slope, $m$, and a point on the line, $(x_{1}, y_{1})$, to write it. **2. TRY IT TOGETHER...

# Writing Linear Equations in Point-Slope Form **WHAT IS POINT-SLOPE FORM?** 1. Point-slope form of a linear equation is $y - y_{1} = m(x - x_{1})$. It is called point-slope form because it you just need the slope, $m$, and a point on the line, $(x_{1}, y_{1})$, to write it. **2. TRY IT TOGETHER!** Use point and slope given to write a linear equation in point-slope form. a) slope: $8$ $m$ point: $(5, 2)$ $y - y_{1} = m(x - x_{1})$ $y - 2 = 8(x - 5)$ b) slope: $-\frac{1}{3}$ $m$ point: $(6, -2)$ $y - y_{1} = m(x - x_{1})$ $y - (-2) = -\frac{1}{3}(x - 6)$ $y + 2 = -\frac{1}{3}(x - 6)$ c) slope: $0$ $m$ point: $(-3, 4)$ $y - y_{1} = m(x - x_{1})$ $y - 4 = 0(x - (-3))$ $y - 4 = 0(x + 3)$ $y - 4 = 0$ d) slope: $-3$ $m$ point: $(2.2, 4)$ $y - y_{1} = m(x - x_{1})$ $y - 4 = -3(x - 2.2)$ **3. TRY IT ON YOUR OWN!** Use point and slope given to write a linear equation in point-slope form. a) slope: $-2$ point: $(6, 7)$ b) slope: $\frac{1}{2}$ point: $(-8, 3)$ c) slope: $5$ point: $(1.1, -3)$ d) slope: $0$ point: $(-10, 9)$ **4. What two variables are in all 3 forms of linear equations?** $x$ and $y$ Did you substitute any values in for those in questions 2 and 3? **5. ERROR ANALYSIS** Describe and correct the error in writing an equation of the line that passes through the point (4, -5) and has slope -2. **Incorrect:** $y + (-5) = -2(x - 4)$ **Correct:** $y - (-5) = -2(x - 4)$ or $y + 5 = -2(x - 4)$