Page 187 - Algebra 1

Solving for Variables on Both Sides
Solve for p: 4p + 2a - 5 = 6a + p. Justify each step. SOLUTION
Example
2
4p+2a-5= -p=
6a+p -p
Eliminate the p on the right side.
Combine like terms.
Eliminate the 2a and -5 from the left side. Combine like terms.
Divide both sides by 3.
Simplify.
A formula is a type of literal equation. Use inverse operations to isolate any variable in the formula.
Solving a Formula for a Variable
The formula C = _5 (F -32) expresses Celsius temperature in terms of 9
Fahrenheit temperature. Find the Fahrenheit temperature when the Celsius temperature is 20°.
SOLUTION
Step1: SolveforF.Justifyeachstep. C = _5 ( F - 3 2 )
__ 3p+2a-5=
__
-_ 2 _ a _ + _ 5 = 3p=
6a
-_ 2 _ a _ + _ 5 4a+5
3p = 4a + 5 ___
333 __
p = 4a + 5 33
Example
3
Hint
Remember that dividing by a fraction is the same as multiplying by the reciprocal.
9
_9 ·C=_9·_5(F-32) 559
_9 C = F -32 5
MultiplicationPropertyofEquality
Simplify.
Addition Property of Equality Simplify.
+_3_2 = +_3_2 _9 C + 32 = F
5
Step2: Substitute20forC.
_9 C + 3 2 = F 5
_9 ( 2 0 ) + 3 2 = F 5
36 + 32 = F 68 = F
20°C is equivalent to 68°F.
172 Saxon Algebra 1