California Algebra 1, 2008

 PAGE: 275 SET: Exercises PROBLEM: 1

The equations are

Equation (1)

Equation (2)

Multiply the first equation by 4.

(Distributive property: )

(Multiply: )

(Multiply: )

Equation (3)

Since the coefficients of the y-terms are additive inverses, y-terms can be

eliminated by adding the equations 2 and 3.

Write the equations in column form and add the corresponding columns.

Apply division property of equality: if a = b then

(Divide each side by  negative 3)

(Cancel commen terms)

(Divide: )

Now Substitute   in either equation to find the value of y.

(Equation 1)

(Multiply: )

(Subtract 4 from each side)

(Apply commutative proparty: a+b=b+a)

(Subtract: )

(Multiply each side by negative one)

(Product of two same signs is positive)

(Product of two different signs is negative)

The solution is ,.

The solution is .

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