Core Connections Algebra 2, 2013
CC
Core Connections Algebra 2, 2013 View details
1. Section 7.1
Continue to next subchapter

Exercise 68 Page 331

Practice makes perfect
a

We can solve the equation by performing inverse operation until x is isolated.

3/x+1=4/x
3x/x+1=4
3x=4(x+1)
3x=4x+4
- x=4
x=- 4

b

We can solve the equation by performing inverse operation until x is isolated. However, first we should add the fractions on the left-hand side by giving them the same denominator.

3/x+1+4/x=2
3/x+1+4(x+1)/x(x+1)=2
3x/x(x+1)+4(x+1)/x(x+1)=2
3x+4(x+1)/x(x+1)=2
3x+4(x+1)=2x(x+1)
3x+4x+4=2x^2+2x
7x+4=2x^2+2x
4=2x^2-5x
0=2x^2-5x-4

We can solve this equation by using the Quadratic Formula.

0=2x^2-5x-4
x=-( - 5) ± sqrt(( - 5)^2-4 * 2( - 4))/2 * 2
x=5 ± sqrt((- 5)^2-4 * 2(- 4))/2 * 2
x=5 ± sqrt(25+32)/4
x=5 ± sqrt(57)/4
lx=.(4+sqrt(57)) /4. x=.(4-sqrt(57)) /4.
lx=-0.63745... x=3.13745...
lx_1=-0.64 x_2=3.14

c

Let's try to solve the equation in the same way as in Parts A and B.

3/x+2+5=3/x+2
5≠ 0

The equation has no solution.

d

An equation states that what is on the left-hand side and on the right-hand side are equal. Examining the equation, we notice that the two sides have an identical term.

3/x+2+5= 3/x+2 If we add or subtract something to either side of the equation, we have to add or subtract the same thing to the other side. However, in the equation from Part C, we have only added 5 to the left-hand side. Therefore, this equation cannot have a solution, as the left-hand side will always be 5 greater than the right-hand side.