Literal Equations

I can solve for a specific unknown variable.

6 ft

10 ft

Find the Area of the given rectangle.

What information do you need to find the area?

You need:

1.The formula for area of a rectangle

2. Identify the Length

3. Identify the Width

A = LW

L = 6

W = 10

Now substitute what you know in to the formula.

A = L WA = 6 WA = 6(10)

A = 60 ft2

7 ft

Unknown

Find the Length of the Given rectangle

What information do you need to find the length?

You need:

1.The formula for area of a rectangle

2. Identify the Length

3. Identify the Width

A = LW

L = unknown

W = 7Now substitute what you know in to the formula.

A = L W

A = 91 ft2

91= L W91= L W 7

91= L 7 791= L 7

Reduce, if possible 13= L

W

LYou need:

1.The formula for area of a rectangle

2. Identify the Length

3. Identify the Width

A = LW

W

A

What do you do if you aren’t given any numbers, but you are still asked to solve for a specific variable?

Solve for W in this equation.

L

A = LW

Solve for W in this equation.

A = LWL L

A = WL

Your science teacher will call this—

“isolating the variable”

Solve for x.

2(x -1) = -42x – 2 = -4 + 2 +2

2x = -2

2 2x = -1

a(x -b) = c

ax – ab = c + ab + ab

ax = c + ab a ax = c + ab

a

x + 5 = 74

( (

4 (4)

x + 5 = 28- 5 -5

x = 23

x + a = c Solve for x.

b

(

b ( ( )b

x + a = c b -a -a

x = c b - ax = bc - a

Solve for the indicated variable in parenthesis.

y = 3x – 7 (x) + 7 + 7

y + 7 = 3xy + 7 = 3x

y = 3x – 7 (x)

3 3

y + 7 = x3

Solve for the indicated variable in parenthesis.

E = mc2 (m) E = mc2

c2c2

E = mc2

Solve for the indicated variable in parenthesis.

3x + 2y = 8 (y)3x + 2y = 8-3x -3x

2y = 8 – 3x2 2

y = 4 – 3x2

Assignment

• Literal Equations worksheet

I can solve for a specific

unknown variable.