Section 2-4: Writing Linear Equations We have already seen standard form of an equation, but this form isn’t very useful. We are going to use slope-int. and point-slope form to write equations.

Slope-Intercept Form y = ______ [ ____ = mx + b] Remember, MOST of the time we will still have ______ in the final equation. m is the _______ b is the __________

Write the equation of the line. First (and easiest) b = ? b = m = ? m = y = x y

Write the equation of the line. b = ? b = m = ? m = y = x y

Write the equation of the line. b = ? b = m = ? m = y = x y

Give the slope and y-int. of each equation. y = -4x + 3 m = b = y = 5 - 1/2x 8x + y = 3/4 m = b = 4x - 2y = 10

Give the slope and y-intercept of each line. y = -1/3x m = b = y = 5 m = b =

Given the slope and y-int., write the equation of the line. m = 0, b = 10 m = 1, b = 0 m = 0, b = 0 m = -3, b = 1 m = -2/5, b = -4

Given the graph, write the equation of the line. To write the equation of a line, we need two pieces of information: ___________ ________________ You should be able to get these from _________.

Point-Slope Form Use this form if you are given _________, or a __________. (as long as the pt. isn’t b) ____________________ (x1, y1) is one of the given points. Use the points to calculate m.

Give the equation of the line. the line goes through (3, 2) & (5, 4). m = choose either point, we’ll use (3, 2). Plug in 3 for ___ & 2 for ____. ____________

Write the equation. y - 2 = 1(x - 3) Simplify. ______________ add two to both sides __________

Give the equation of the line through the points (4, 3) and (7, -2) m = plug either point. y - 3 = y =

Give the equation of the line with x-int. 3 and y-int 2. Because we know the y-int. (b), we only need the slope. m = y =