1. Bell Ringer Solve each equation for y. 1) 3x + y = 5 2) x – y = 6 3) 20x + 4y = 8 Clear each equation of decimals. 4) 6.25x + 8.5 = 7.75 5) .4 = .2x - 5
2. Standard form of a linear equation Ax + By = C. X – intercept is where the line crosses the x-axis. Y – intercept is where the line crosses the y-axis. What are x- and y – intercepts?
3. x- and y-coordinates
4. To find x – intercept, you substitute 0 for y then solve for x. To find y – intercept, you substitute 0 for x then solve for y. X – and Y- intercepts as points: X – intercept : Y – intercept : (x, 0) (0, y)
5. Practice finding intercepts Find the x-intercept: 2x + 4y = 8. 2x + 4(0) = 8 2(0) + 4y = 8 Find the y - intercept.
6. Practice finding intercepts Find the x-intercept: -x + 3y = 9. -x + 3(0) = 9 -(0) + 3y = 9 Find the y - intercept.
7. Find the x- and y – intercepts of: You try! 2x + 5y = 6 3x + 5y = 15 4x – 9y = 12 x + 2y = 8 -6x + 3y = -9
8. Find the intercepts for -3x + y = 6. Then graph your points.
9. Find the intercepts and graph: x - y = -7 2x + y = 2 You try!
10. 2 x -5 y = 10 x + y = 2 Find the intercepts and graph: You try!
11. Graphing horizontal and vertical lines Horizontal Lines y = # Vertical Lines x = #
12. For each equation, tell whether its graph is a horizontal or vertical line. x = 4 y = ½
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