Core Connections Geometry, 2013
CC
Core Connections Geometry, 2013 View details
3. Section 1.3
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Exercise 114 Page 65

Practice makes perfect
a To solve an equation, we should first gather all of the variable terms on one side of the equation and all constants on the other side by using the Properties of Equality. In this case, we will start by multiplying both sides of the equation by the lowest common denominator to remove the fractions.
3x-1/4=- 5/11
LHS * 44=RHS* 44
3x-1/4(44)=- 5/11(44)
3x-1/4(4)(11)=- 5/11(11)(4)
(3x-1)(11)=- 5/11(11)(4)
(3x-1)(11)=- 5(4)
33x-11=- 5(4)
33x-11=- 20
33x=- 9
x=- 9/33
Simplify
x=- 9/33
x=- 3/11
The solution to the equation is x=- 311. We can check our solution by substituting it into the original equation.
3x-1/4=- 5/11
3( - 311 ) -1/4 ? = - 5/11
Simplify
- 3( 311 ) -1/4 ? = - 5/11
- 911 -1/4 ? = - 5/11
- 911 - 1111/4 ? = - 5/11
- 2011/4 ? = - 5/11
- 20/4(11) ? = - 5/11
- 5/11 ? = - 5/11
- 5/11=- 5/11 ✓
Since the left-hand side is equal to the right-hand side, our solution is correct.
b To solve this equation, we should apply the Zero Product Property. After obtaining two equations, in both of them we will gather all of the variable terms on one side of the equation and all of the constant terms on the other side by using the Properties of Equality.
(5-x)(2x+3)=0
l5-x=0 2x+3=0
Now we can continue to solve using the Properties of Equality.
lc5-x=0 & (I) 2x+3=0 & (II)
(I): Solve for x
l5=x 2x+3=0
lx=5 2x+3=0
(II): Solve for x
lx=5 2x=- 3
lx=5 x= - 32
lx_1=5 x_2=- 32
The solutions to the equation are 5 and - 32. We can check our solution by substituting them into the original equation. Let's start with x=5.
(5-x)(2x+3)=0
(5- 5)(2( 5)+3) ? = 0
Simplify
(0)(2(5)+3) ? = 0
0=0 ✓
Since substituting and solving resulted in a true statement, we know that x=5 is a solution of the equation. Let's now check x=- 32.
(5-x)(2x+3)=0
(5-( - 3/2))(2( - 3/2)+3) ? = 0
Simplify
(5-(- 3/2))(- 2 ( 3/2)+3) ? = 0
(5-(- 3/2))(- 3+3) ? = 0
(5-(- 3/2))(0) ? = 0
0=0 ✓
This is also a true statement, so we know that x=- 32 is a solution of the equation.
c To solve an equation, we should first gather all of the variable terms on one side of the equation and all of the constant terms on the other side by using the Properties of Equality. In this case, we need to start by using the Distributive Property to simplify the left-hand side of the equation.
6-5(2x-3)=4x+7
6-5(2x)-5(- 3)=4x+7
6-10x-5(- 3)=4x+7
6-10x+15=4x+7
Now we can continue to solve using the Properties of Equality.
6-10x+15=4x+7
21-10x=4x+7
14-10x=4x
14=14x
14x=14
x=1
The solution to the equation is x=1. We can check our solution by substituting it into the original equation.
6-5(2x-3)=4x+7
6-5(2( 1)-3) ? = 4( 1)+7
Simplify
6-5(2-3) ? = 4+7
6-5(- 1) ? = 11
6+5 ? = 11
11 = 11 ✓
Since the left-hand side is equal to the right-hand side, our solution is correct.
d To solve an equation, we should first gather all of the variable terms on one side of the equation and all constants on the other side by using the Properties of Equality. In this case, we will start by multiplying both sides of the equation by the lowest common denominator to remove the fractions.
3x/4+2=4x-1
3x/4(4)+2(4)=4(4)x-1(4)
3x/4(4)+8=16x-4
3x+8=16x-4
Now we can continue to solve using the Properties of Equality.
3x+8=16x-4
3x+12=16x
12=13x
12/13=x
x=12/13
The solution to the equation is x= 1213. We can check our solution by substituting it into the original equation.
3x/4+2=4x-1
3( 1213 )/4+2 ? = 4( 12/13 )-1
Simplify
3613/4+2 ? = 48/13-1
36/4(13)+2 ? = 48/13-1
9/13+2 ? = 48/13-1
9/13+26/13 ? = 48/13-13/13
35/13=35/13 ✓
Since the left-hand side is equal to the right-hand side, our solution is correct.