Solve and Graph 2x + 3 < 9 2x + 3 = 9 -3 -3 2x = 6 2 2 x = 3 Solve a similar equation to find the dividing point. 2x + 3 = 9 -3 -3 2x = 6 2 2 x = 3 This is the dividing point. Plot in on the number line. Test a point. Test x = 0 -2 -1 0 1 2 3 4 5 2(0) + 3 < 9 0 + 3 < 9 x < 3 3 < 9 True. Write the solution. Shade the side with 0.
2.5: LINEAR INEQUALITIES Example: 5x – 2y 8 + 3x 5x – 2y = 8 + 3x 1. Write a similar _____________ . EQUATION –2y = -2x + 8 Replace < or > with =. –2 -2 -2 2. Solve for y. y = x - 4 This is your ___________ _______. BOUNDARY LINE y 6 3. Draw a graph. 4 4. Graph Boundary Line. 2 x DASHED Line if < or > SOLID Line if or . -6 -4 -2 2 4 6 -2 -4 -6
False 5x – 2y 8 + 3x Test: (0, 0) 5(0) – 2(0) 8 + 3(0) 0 8 + 0 5. Test a point. 5(0) – 2(0) 8 + 3(0) Any point except points on dividing line. Identify your test point. Check in ORIGINAL problem. Show work when you substitute. Write True or False. 0 8 + 0 0 8 FALSE! x y 2 4 6 -2 -4 -6 6. Shade towards TRUTH. False Test Point TRUE: Shade SIDE w/ point. Test Point FALSE: Shade OTHER SIDE. 7. Write solution in y form. If below boundary line, then < or If above boundary line, then > or y ≤ x – 4
Graph the inequality Boundary line: Test point (0, 0) y-int: (0,-3) x 1 2 3 4 5 -1 -2 -3 -4 -5 Test point (0, 0) y-int: (0,-3) True Shade the side with (0, 0).
Graph the inequality Boundary line: Test point (0, 0) y-int: (0,1) x 1 2 3 4 5 -1 -2 -3 -4 -5 Boundary line: Test point (0, 0) y-int: (0,1) False