Transcript Literal Equations - Ms. Tran's Classes

EQUATIONS
FOR A
VARIABLE
California
Standards
Extension of
5.0 Students solve multistep
problems, including word problems, involving
linear equations and linear inequalities in one
variable and provide justification for each step.
A formula is a type of literal equation. A literal
equation is an equation with two or more variables.
To solve for one of the variables, use inverse
operations.
Solving for a Variable
Step 1 Locate the variable you are asked to
solve for in the equation.
Step 2 Identify the operations on this
variable and the order in which they
are applied.
Step 3 Use inverse operations to undo
operations and isolate the variable.
1) Solve 2x - 4y = 7 for x
1.
2.
3.
4.
Add 4y to both
sides
Simplify
Divide both sides by
2
Does it simplify?
2x - 4y = 7
+ 4y + 4y
2x = 7 + 4y
2
2
7  4y
x
2
This fraction cannot be simplified
because both terms in the numerator
are not divisible by 2.
2) Solve 2x - 4y = 7 for y
To get y by itself, what is the first step?
1. Add 2x
2. Subtract 2x
3. Add 4y
4. Subtract 4y
Answer Now
3) Solve 2x - 4y = 7 for y
1. Subtract 2x from
both sides
2. Simplify
3. Divide both sides
by -4
4. Does it simplify?
2x - 4y = 7
-2x
- 2x
-4y = 7 - 2x
-4
-4
7  2x
y
4
Nope!
4) Solve for y: 4x – 2y = 12
1. Subtract 4x from
both sides
2. Simplify
3. Divide both sides
by -2
4. Does it simplify?
Yes!
or
4x – 2y = 12
- 4x
- 4x
-2y = 12 – 4x
-2
-2
y = -6 + 2x
y = 2x - 6
5) Solve for y: 4x – 2y = 12
1.
2.
3.
4.
-4x + 12
4x - 12
-2x + 6
2x - 6
Answer Now
9x – 7y = -7
1. Solve for x
2. Solve for y
Lesson Quiz: Part I
Solve for the indicated variable.
1.
2.
for h
P = R – C for C
C=R–P
3. 2x + 7y = 14 for y
4.
for m
5.
for C
m = x(k – 6)
C = Rt + S
Lesson Quiz: Part II
Euler’s formula, V – E + F = 2, relates the number
of vertices V, the number of edges E, and the
number of faces F of a polyhedron.
6. Solve Euler’s formula for F. F = 2 – V + E
7. How many faces does a polyhedron with 8
vertices and 12 edges have? 6