6.1 Solving One-Step Linear Inequalities x + 8 > 1

1. 6.1 Solving One-Step Linear Inequalities x + 8 > 1 6.2 Solving Multi-step Linear Inequalities 5x – 3 > 12 6.3 Solving Compound Inequalities -5<2x + 3 < 7 6.4 Solving Absolute-value Equations and Inequalities |x-4|=8 |5x+1|+3 =14 6.5 Graphing Linear Inequalities in Two Variables Graph x + y > 3

2. 6.6 Stem and leaf plots; mean, median, mode 6.7 Box and whisker plots

3. Ch 7 Systems of Linear Equations and Inequalities Due Tuesday 11/29 7.1 p401 12,16,18, 22,26,36,44 Due Wednesday 11/30 7.2 p408-411 #14,16,18,20, 26, 30,35,44,48-51 Due Thursday 12/1 7.3 p414 #8, 14, 18, 24, 26, 30, 36, 40, 44 Due Friday 12/2 7.3 p414 #45-52, 56; p417 1-9

4. 7.1 Solving systems of linear equations by graphing: Graph-Estimate-Check y=3x-12 and y=-2x+3 (3,-3)

8. 7.1 p401 12,16,18, 22,26,36,44

14. 7.1 Solving a System of Linear Equations by Graphing 7.2 Solving a System of Linear Equations by Substitution

16. Solve by Substitution 3x+y=5 and 2x-y=10 (3,-4)

17. Solve by Substitution 2x+6y=15 and x=2y (3,3/2)

18. Solve by Substitution x+2y=4 and –x+y=-7 (6,-1)

20. Homework: p408-411 #14,16,18,20, 26, 30,35,44,48-51

26. 7.1 Solving a System of Linear Equations by Graphing 7.2 Solving a System of Linear Equations by Substitution 7.3 Solving Linear Systems by Linear Combination Solving by graphing can be challenging Substitution is easier than graphing, but sometimes it is not easy to isolate the variable. …let’s try Linear Combination -x+2y=-8 x+6y=-16 x+6y=-16 8y=-24 y=-3 To find x, plug in -3 into one of the equations x+6(-3) = -16 x-18=-16 x=2 solution (2, -3) Check -2+2(-3)=-8

27. Solve by linear combination:3x-6y= -12 -x+3y=6 3x -6y= -12 -3x+9y= 18(multiply each term by 3) 3y=6 y=2 To find x: 3x-6(2)= -12 3x=0 x=0 Check: -(0) +3(2) = 6 3(0)-6(2)=-12 Solution: (0,2) Solve by linear combination: 5x-4y=3 2x+8y=-2 2(5x)-2(4y) = 2(3) (multiply first equation by 2 to get y’s to cancel) 10x -8y =6 2x + 8y = -2 12x = 4 x= 1/3 To find y: 2(1/3)+8y= -2 2/3 +8y = -2 8y=-2 2/3 8y= -8/3 y=-1/3 Check: 5(1/3) -4(-1/3) = 3 2(1/3) +8(-1/3)= -2 Solution: (1/3, -1/3)

28. Solve by linear combination: 2u=4v+8 3v=5u-13 2u-4v=8 -5u+3v= -13 (reorganize so variables on same side) 10u – 20v =40 (to get “u” to cancel, multiple top equation by 5) -10u +6v = -26 (to get “u” to cancel, multiple bottom equation by 2) -14v=14 v=-1 2u=4(-1)+8 (to find “u”, plug in v=-1 into one of the equations) 2u=4 u=2 Check: 2(2)=4(-1)+8 3(-1)=5(2)-13 Solution: (u,v)=(2, -1)

29. 2. When the 2nd equation was multiplied by -2, 4y(-2) is not=8y 3. When adding 9x+7x, it is not=2x

30. 3x = 6 (add equations, y’s cancel) x= 2 2-y=2 (insert 2 for x in 2nd equation) -y=0 so y=0 Check 3(2)= 6 and 2-0=2 Solution: (2, 0) -1/2g =4 (add equations, h’s cancel) g=-8 (solve for g) (1/2)(-8)+h=2 (insert -8 for g in 1st equation) -4+h=2 h=6 Check: (1/2)(-8)+6=2 ; -(-8)-6=2 Solution: (-8, 6) 7.3 p414 #8, 14, 18, 24, 26, 30, 36, 40, 44

31. -x-3y=-3 (multiply 1st equation by -1) x+6y=3 3y=0 y=0 x+3(0)=3 (insert 0 for y in 1st equation) x=3 Check: 3+3(0)=3; 3+6(0)=3 Solution: (3,0) 9x -3z =20 -9x-18z=-6(multiply 2nd equation by -3) -21z=14 z=-2/3 9x-3(-2/3)=20 (insert -2/3 for z in 1st equation) 9x+2=20 9x=18 x=2 Check: 9(2)-3(-2/3)=20 3(2)+6(-2/3)=2 Solution: (2, -2/3) 7.3 p414 #8, 14, 18, 24, 26, 30, 36, 40, 44

32. 3b +2c=46 -3b-15c=-33(multiply 2nd equations by -3) -13c=13 c=-1 3b+2(-1)=46 3b=48 b=16 Check: 3(16)+2(-1)=46 5(-1)+16=11 Solution: (16, -1) 0.1g-h=-4.3 (subtract -4.3 from both sides) -0.2g+h=3.6(reorganize & multiply by -1) -0.1g=-0.7 g=7 0.1(7)-h+4.3=0 (insert 7 for g in 1st equation) .7-h+4.3=0 5=h Check: 0.1(7)-5+4.3=0 3.6=-0.2(7)+5 Solution: (7,5) 7.3 p414 #8, 14, 18, 24, 26, 30, 36, 40, 44

33. Solve by linear combination: 4a+b=0 (reorganize 1st equation) 1a-b=5 (reorganize 2nd equation) 5a=5 a=1 3(1)+9b=8b-1 (insert 1 for a in 1st equation) 4=-b b=-4 Check: 3(1)+9(-4)=8(-4)-1 5(1)-10(-4)=4(1)-9(-4)+5 Solution: (1,-4) 1.5v-6.5w=3.5 -1.5v-6w=9(multiply 2nd equation by -3) -12.5w=12.5 w=-1 0.5v+2(-1)=-3 0.5v-2=-3 0.5v=-1 v=-2 Check: 1.5(-2)-6.5(-1)=3.5 0.5(-2)+2(-1)=-3 Solution: (-2,-1)

34. y=(9/7) x y=-3x+12 7y=9x (multiplied 1st equation by 7) -7y=21x-84 (multiplied 2nd equation by -7) 0=30x-84 30x=84 x=14/5 y=-3(14/5)+12= -8 2/5 +12= 3 3/5 solution: (14/5, 18/5) Check: 18/5 = (9/7) (14/5) 18/5 = -3(14/5) + 12

35. s=speed in still air • w=wind speed • s-w =300 • s+w=450 • 2s=750 • s=375 • If s=375, then 375-w=300 • w=75 • Check: 375-75=300 • 375+75=450 • 375mph =speed of plane • 75mph =speed of wind p414 #45-52, 56; p417 1-9

36. 48) boat traveled upstream 8 miles in 1 hour boat traveled downstream 8 miles in ½ hour b-w=8 boat speed-speed of water = 8 mph b+w=16 boat speed +speed of water=16 mph 2b=24 b=12 w=4 Boat was traveling at 12 mph, water was going 4mph. p414 #45-52, 56; p417 1-9

38. Quiz Prep

44. Ch 7 Systems of Linear Equations and Inequalities Due Monday 12/5 7.4 p421 #12, 20, 28, 42, 48; chapter 1 summary p54-56 Due Tuesday 12/6 7.5 p429 #12-17,18,24,30,43-46; chapter 2 review Due Wednesday 12/7 7.6 p435 #9-14, 26; chapter 3 review Due Thursday 12/8 7.6 p435 # 37,43; chapter 4 review Due Friday 12/9 chapter 7 review p440 #2-32 (pick one in each section)

45. 7.4 Applications of Linear Systems

47. What would you use to solve this system of equations? Why?

48. Cr+cp=32.75 Cp=cr+.2 Total cost regular + total cost premium =$32.75 Cost premium = cost regular + .2 Regular gas amount (cost) + premium gas amount (cost)=$32.75 10c + 15(c+.20) = 32.75 25c +3 =32.75 25c = 29.75 c=$1.19 cost for regular, $1.39 cost for premium To check: 10(1.19) + 15(1.19+.20)=32.75

49. 2x – y = 3 2x - 3 = y 4x + 3(2x-3) = 21 4x + 6x – 9 = 21 10x = 30 x = 3 4(3) + 3y = 21 12 + 3y = 21 3y = 9 y = 3 (3,3) Check: 2(3) -3 = 3 4(3) + 3(3) = 21

50. -x + -2y = -2 (multiply 1st equation by -1) x + 4y = -2 2y =-4 y = -2 x + 2(-2) = 2 x=6 (6, -2) Check: 6 + 2(-2) = 2 6 + 4 (-2) = -2