Exercise 7 Page 221

Does substituting the point into every equation in the system result in true statements?

Yes

Practice makes perfect

To determine if a point satisfies an equation, we substitute the point into the equation and simplify. If the resulting statement is true, the point is a solution of the equation. For systems of equations, we can use the same method, but substituting the point must create true statements in every equation in the system. Let's test the given point.

6x+5y=- 7 & (I) 2x-4y=- 8 & (II)

SubstituteII

x= - 2, y= 1

6( - 2)+5( 1)? =- 7 2( - 2)-4( 1)? =- 8

(I), (II): Identity Property of Multiplication

6(- 2)+5? =- 7 2(- 2)-4? =-8

(I), (II): a(- b)=- a * b

- 12+5? =- 7 - 4-4? =- 8

AddSubTerms

Add and subtract terms

- 7=- 7 ✓ - 8=- 8 ✓

Since - 7 is equal to - 7 and - 8 is equal to - 8, both statements are true. Therefore, the point (- 2,1) is a solution of the system.

Subchapter links

Communicate Your Answer p.217

Monitoring Progress p.218-220

Exercises p.221-222

Exercise 7 Page 221

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