Question

15 9 - 3x - (-8y) + 9x - y + 8y - 9
16 x - 4y - 12 - 5y + 8y
17 3x + 7 - 7y + 2x - 3y - 1
18 -9x - y + 1 + 5y + 5x - 10

Explanation:

Let's solve problem 15: \( 9 - 3x - (-8y) + 9x - y \)

Step1: Simplify signs

\( 9 - 3x + 8y + 9x - y \)

Step2: Combine like terms for \( x \)

\( (-3x + 9x) = 6x \)

Step3: Combine like terms for \( y \)

\( (8y - y) = 7y \)

Step4: Combine constant terms

Constant term is \( 9 \)

Step5: Write the simplified expression

\( 6x + 7y + 9 \)

Now problem 16: \( x - 4y - 12 - 5y + 8 \)

Step1: Combine like terms for \( y \)

\( (-4y - 5y) = -9y \)

Step2: Combine constant terms

\( (-12 + 8) = -4 \)

Step3: Write the simplified expression

\( x - 9y - 4 \)

Problem 17: \( 3x + 7 - 7y + 2x - 3y - 1 \)

Step1: Combine like terms for \( x \)

\( (3x + 2x) = 5x \)

Step2: Combine like terms for \( y \)

\( (-7y - 3y) = -10y \)

Step3: Combine constant terms

\( (7 - 1) = 6 \)

Step4: Write the simplified expression

\( 5x - 10y + 6 \)

Problem 18: \( -9x - y + 1 + 5y + 5x - 10 \)

Step1: Combine like terms for \( x \)

\( (-9x + 5x) = -4x \)

Step2: Combine like terms for \( y \)

\( (-y + 5y) = 4y \)

Step3: Combine constant terms

\( (1 - 10) = -9 \)

Step4: Write the simplified expression

\( -4x + 4y - 9 \)

Answer:

1. \( 6x + 7y + 9 \)
2. \( x - 9y - 4 \)
3. \( 5x - 10y + 6 \)
4. \( -4x + 4y - 9 \)