Core Connections: Course 3
CC
Core Connections: Course 3 View details
1. Section 6.5
Continue to next subchapter

Exercise 38 Page 238

In a system of equations, if the left-hand sides of both equations are equal, the right-hand sides also are equal.

(a,b) = (-3, - 1/2)

Practice makes perfect
We want to solve the following system of equations using the Equal Values Method. a=12b+3 & (I) a = -2 b-4 & (II) In the given system, the left-hand sides of both equations are equal to each other — both are equal to a. That relationship means the right-hand sides of both equations are also equal to each other. The variable a can then be replaced by the right-hand sides, respectively. a= 12b+3 a = -2 b-4 ⇓ 12b+3 = -2 b-4 We know have an equation only in terms of b. Let's solve it!
12b+3 = -2 b-4
14b+3= -4
14b = -7
b = -7/14
Simplify right-hand side
b = -1/2
b = -1/2
Now that we know the value of b, let's substitute it into Equation (II). We will get an equation only in terms of a. Then, let's solve our updated equation!
a = -2 b-4
a = -2( -1/2 ) -4
a = -2( 1/-2 ) -4
a = 1 - 4
a = -3
Great work! We have one solution to our system of equations. (a, b) = ( -3, - 12)