Graphing Linear Inequalities Unit 5 Stephen makes $10 per hour working at QT and $5 per hour babysitting. – He wants to save at least $50 to buy a Wii game. – He doesn’t really like working at QT because . . . well, it’s work. It pays better than babysitting though. – He would rather babysit to earn money because he can watch TV and text his friends. He just wished he got paid more to do basically nothing. Stephen makes $10 per hour working at QT and $5 per hour babysitting. – What are the possible hours that he could work to get the money? – First the equation Ax + By = C or in this case 10Q + 5B = 50. – Wait a minute. The equals means that Stephen only wants to make $50. The original question said that he wanted to make AT LEAST $50. That’s different. Stephen makes $10 per hour working at QT and $5 per hour babysitting. • That involved an inequality. • So our problem is not 10Q + 5B = 50, it’s 10Q + 5B ≥ 50 • Now we need to graph it. Remember, we are going to solve this like it is an equation so that we can solve for Q (like x) and B (like y). Stephen makes $10 per hour working at QT and $5 per hour babysitting. 10Q + 5B = 50 10Q + 5(0) = 50 10Q + 0 = 50 10Q = 50 10 10 Q=5 The B is now a zero so we can find the x-intercept. 5 times 0 is zero. Get rid of it. Divide both sides by 10. The x-intercept is (5,0) Stephen makes $10 per hour working at QT and $5 per hour babysitting. 10Q + 5B = 50 10 (0) + 5B = 50 0 + 5B = 50 5B = 50 5 5 B = 10 The Q is now a zero so we can find the y-intercept. 10 times 0 is zero. Get rid of it. Divide both sides by 5. The y-intercept is (0, 10) Stephen makes $10 per hour working at QT and $5 per hour babysitting. Get the Coach book from under your desk. • Turn to p. 189. Test Wednesday Know the Slope Formula and the Slope Intercept Form. Know the variables and meanings of slope and yintercept of the Slope Intercept Form, y = mx + b. Know how to solve the slope from the Slope Formula m = y2 – y1 x2 – x1 HW – Due Th/Fri • Worktext p. 405 & 406