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Beginning Activity Beginning Activity 2: Linear Equations in Two Variables

1.

Find integers x and y so that 2x+6y=25 or explain why it is not possible to find such a pair of integers.

2.

Find integers x and y so that 6x9y=100 or explain why it is not possible to find such a pair of integers.

3.

Notice that x=2 and y=1 is a solution of the equation 3x+5y=11, and that x=7 and y=2 is also a solution of the equation 3x+5y=11.

(a)

Find two pairs of integers x and y so that x>7 and 3x+5y=11. (Try to keep the integer values of x as small as possible.)

(b)

Find two pairs of integers x and y so that x<2 and 3x+5y=11. (Try to keep the integer values of x as close to 2 as possible.)

(c)

Determine formulas (one for x and one for y) that will generate pairs of integers x and y so that 3x+5y=11.

Hint.

The two formulas can be written in the form x=2+km and y=1+kn, where k is an arbitrary integer and m and n are specific integers.

4.

Notice that x=4 and y=0 is a solution of the equation 4x+6y=16, and that x=7 and y=2 is a solution of the equation 4x+6y=16.

(a)

Find two pairs of integers x and y so that x>7 and 4x+6y=16. (Try to keep the integer values of x as small as possible.)

(b)

Find two pairs of integers x and y so that x<4 and 4x+6y=16. (Try to keep the integer values of x as close to 4 as possible.)

(c)

Determine formulas (one for x and one for y) that will generate pairs of integers x and y so that 4x+6y=16.

Hint.

The two formulas can be written in the form x=4+km and y=0+kn, where k is an arbitrary integer and m and n are specific integers.