6) \( a x+b x+a y+b y \) 7) \( b x+5 b+2 x+10 \) 8) \( 2 a b-10 a+3 b-15 \) 9) \( x^{2}-y^{2}+5 x-5 y \) 10) \( x^{3}+y^{2}+9 x+9 \)

To simplify the given expressions, we will combine like terms. 1. \( a x + b x + a y + b y \) - Combine like terms: \( (a + b)x + (a + b)y \) 2. \( b x + 5b + 2x + 10 \) - Combine like terms: \( (b + 2)x + (5b + 10) \) 3. \( 2ab - 10a + 3b - 15 \) - Combine like terms: \( 2ab - 10a + 3b - 15 \) (no like terms to combine) 4. \( x^{2} - y^{2} + 5x - 5y \) - Combine like terms: \( x^{2} - y^{2} + 5x - 5y \) (no like terms to combine) 5. \( x^{3} + y^{2} + 9x + 9 \) - Combine like terms: \( x^{3} + y^{2} + 9x + 9 \) (no like terms to combine) Therefore, the simplified expressions are: 1. \( (a + b)x + (a + b)y \) 2. \( (b + 2)x + (5b + 10) \) 3. \( 2ab - 10a + 3b - 15 \) 4. \( x^{2} - y^{2} + 5x - 5y \) 5. \( x^{3} + y^{2} + 9x + 9 \)