SOLVE IT
Solve: X+7=15
X=22
What is the first step? X+6=14
Subtract 6 from both sides.
Solve for X: X+a=b
X=a-b
Turn this into an equation: A number plus 8 equals 20.
X+8=20
How many solutions: X+4=X+4
Infinitely Many Solutions (IMS)
Solve: 3X=21
X=7
What is the first step? X-9=12
Add 9 to both sides.
Solve for X: ax=b
X=a/b
Turn this into an equation: Five more than twice a number is 17.
5+2X=17 or 2X+5=17
How many solutions: 2X+5=2X+5
Infinitely Many Solutions (IMS)
Solve: 2X+5=17
X=6
What is the first step? 5X=35
Divide both sides by 5.
Solve for X: aX-b=c
X= (c-b)/a
Turn this into an equation: A gym charges $10 plus $5 per visit.
10+5X or 5X+10
How many solutions: 4(X+2)=4X+8
Infinitely Many Solutions (IMS)
Solve: 3(X+4)=24
X=4
What is the first step?
X+7 2
—— = ——
2 4
Cross multiply. (Butterfly trick)
Solve for X: a(X+b)=c
X=(c/a)-b
You have $48 and each game costs $8. How many can you buy?
48=8X —> 6 games
How many solutions: 3X+2=3X+7
No Solution
Solve: (X+4)/3=6
X=18
What is the first step? 2(x+4)=18
Distribute the 2.
Solve for X: (X+a)/b=c
X=bc-a
A phone plan costs $25 plus $1 per call. The bill is $37. How many calls did you make?
X+25=37 —> X=12
How many solutions: 5X-3=5X+2
No Solutions