Solving Inequalities
What happens if you multiply or divide by a negative number?
You MUST flip the inequality sign!!
When the Inequality sign eats the variable your arrow points to the ____?
Right or BIG #s
What do you do to solve the following equation?
x/-4+5.2=-8.1
Step 1: Subtract 5.2 from both sides
Step 2: Multiply both sides by -4
Where is the error:
Given: -6(x+3)=78
Step 1: -6x-18=78
Step 2: -6x=60
Step 3: x=-10
Between Step 1 & Step 2
(the inverse of -18 is +18, you should be adding 18 to 78 on the right side instead of subtracting 18)
Solve: -3x>72
x<-24 or -24>x
Match the Inequality Sign with what type of dot you would use on the Graph. (≤, ≥, <, >)
≥ and ≤ means ●
> and < means ○
Solve: 5.20h+52.55=74.65
h=4.25
Where is the error:
Given: -5(x+4)=95
Step 1: -5x-20=95
Step 2: -5x=115
Step 3: x=23
Between Step 2 & Step 3
(positive divided by a negative = negative answer)
Solve: 23.4≥s-14.9
38.3≥s or s≤38.3
Look at the Graph shown on the board, what inequality does it represent?
x > 3
Solve: 9s-253=899
s=128
Where is the error:
Given: -2(x+6)=72
Step 1: -2x+12=72
Step 2: -2x=60
Step 3: x=-30
Between Given & Step 1
(Distributed incorrectly)
Solve: -48>d/2
-96>d or d<-96
What does the graph look like for the Inequality: w+23/3≤15/6
Start at -31/6, closed dot, pointing to Small #s (left)
Solve: 9(p-253)=630
p=323
Write an equation to represent the situation. Use x as your variable:
In one night a server earned $98.25. He earned $6.80 per hour plus $42.15 in tips.
6.80x+42.15=98.25
Solve: y+28/5≤13/10
y≤-43/10 or -43/10≥y
What does the graph look like for the Inequality: -21≤y/2
Start at -42, closed dot, pointing to BIG #s (right)
2 5/6 = 6 2/5 - m
m=3 17/30
Write an equation to represent the situation. Use x as your variable:
Mary is saving for a trip. Every week, after taking out the $279 she needs for weekly expenses, she sets aside the same portion of her paycheck. After 7 weeks, she has $574 saved for her trip.
7(x-279)=574