Big Ideas Math: Modeling Real Life, Grade 8
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Big Ideas Math: Modeling Real Life, Grade 8 View details
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Exercise 24 Page 229

The Elimination Method can be used to solve a system of linear equations if either of the variable terms would cancel out the corresponding variable term in the other equation when added together.

Solutions: Infinitely many solutions.
Explanation: See solution.

Practice makes perfect
We want to solve the given system of linear equations. 3 x-2 y=1 & (I) 9 x-6 y=3 & (II) Since neither equation has a variable with a coefficient of 1, the Substitution Method may not be the easiest. Instead, we will use the Elimination Method. To do that, one of the variable terms needs to be eliminated when one equation is added to or subtracted from the other equation. This means that either the x- or the y-terms must cancel each other out. If we multiply Equation (I) by 3, the y-terms will have opposite coefficients.

( 3)(3 x-2 y)=1( 3) 9 x-6 y=3 ⇓ 9 x- 6y=3 9 x- 6y=3 Notice that both equations are the same. Therefore, there are infinitely many solutions.