2 4 Writing Linear Equations Main Ideas Write

2. 4 Writing Linear Equations Main Ideas • Write an equation of a line given the slope and a point on the line. • Write an equation of a line parallel or perpendicular to a given line.

Forms of Equations Slope-intercept form y = mx + b ▫ Form used to graph a line. ▫ Equation of a vertical line cannot be written in this form because it has an undefined slope. x = a

State the slope and y-intercept of each equation. 1) y = 8 x + 12 2) y = -⅜x 3) 2 x – 3 y = 10 4) y = -x – 4 5) x = 9 6) -x + 5 y = 2

Forms of equations Point-slope form y – y₁ = m(x – x₁) ▫ Form used to write an equation of a line. How to simplify into slope –intercept (y = mx + b) 1) Distribute 2) Add/subtract the number to the right side 1) y – 4 = 2(x + 7)

Write an equation in slope-intercept form for the line that satisfies each set of conditions. 1) Slope ½, passes through (6, 4) 2) Passes through (6, 1) and (8, -4) 3) x-intercept 3, y-intercept 1

Write an equation in slope-intercept form for each graph.

Parallel & Perpendicular lines Parallel lines have the same slope. Perpendicular lines have opposite and reciprocal slopes. Write the equation of the line that is parallel to the given line. Write the equation of the line that is perpendicular to the given line. 1)Passes through (-4, 3) and y = -4 x – 1