Warm Up Todays Objective To be able to

• Warm Up

Today’s Objective • To be able to write a linear equation.

Recall #1 • Slope-intercept form of the equation: • y = mx + b • m is slope and b is the y-intercept.

Recall #1 • y = mx + b • y = 3 x + 2 • 3 is slope and 2 is the y-intercept.

Y = 3 x + 2 Slope = 3/1 y-intercept

Recall #2 • Slope Formula: • m = y 2 - y 1 x 2 - x 1

Recall #2 • (1, 4) and (2, 3) • (x 1, y 1) & (x 2, y 2) • Slope • m = 3 - 4 Formula: • m = y - y 2 -1 x -x 2 2 1 1

Recall #2 • m = 3 - 4 2 -1 • m = -1 1

Write a linear Equation • If f(2) = 5 and f(6) = 3 • f(2) = 5 when x =2 & y = 5 (2, 5) • f(6) = 3 when x = 6 & y = 3 (6, 3)

(2, 5) & (6, 3) When x = 2, f(x) = 5 When x = 6, f(x) = 3

Step 1 find the slope • (2, 5) and (6, 3) • (x 1, y 1) & (x 2, y 2) • Slope • m = 3 - 5 Formula: • m = y - y 6 -2 x -x 2 2 1 1

Step 1 find the slope • m = 3 - 5 6 -2 • m = -2 4

Finish • If m = -1/2 and b = 6, then: • y = -1/2 x + 6 is the equation of the line.

Y = -1/2 x + 6

Your Turn • Write an equation of the line for: f(2) = -2 and f(-4) = 1 • Step 1 find the slope • Step 2 use y = mx + b to find the b value.

Step 1 find the slope • f(2) = -2 and f(-4) = 1 • (2, -2) and (-4, 1) • Slope = y 2 - y 1 x 2 - x 1

Step 1 find the slope • (2, -2) and (-4, 1) • Slope = 1 - -2 -4 - 2 • Slope = 3 -6

Finish • If m = -1/2 & b = -1, then: • y = -1/2 x + -1 is the equation of the line.

• Classwork