[multiplying monomials][section 32]

(1.) x⁴ * x⁵ here is the problem

= x⁹ add exponents

result: x⁹

(2.) (-4x²y)(-5xy) here is the problem

= 20x³y² multiply, add exponents

result: 20x³y²

(3.) (8mn²)(-3m²y⁴) here is the problem

= -24m³n⁶ multiply, add exponents

result: -24m³n⁶

(4.) (4c²d)(5cd)(cd²) here is the problem

= 20c⁴d⁴ multiply add exponents

result: 20c⁴d⁴

(5.) (2x)(3x⁴)(-6x³) here is the problem

= -36x⁸ multiply add exponents

result: -36x⁸

(6.) (-2x⁴)(-3x²) here is the problem

= 6x⁶ multiply add exponents

result: 6x⁶

(7.) (-x⁵)(5xy²)(9x³y²) here is the problem

= -45x⁹y⁴ multiply add exponents
result: -45x⁹y⁴

(8.) (-3a²b)(ab)(-2ab)⁰ here is the problem

= (-3a²b)(ab)(1) anything to the 0 power is 1

= -3a³b² multiply add exponents

result: -3a³b²

(9.) 10³ * 10² * 10⁴ here is the problem

= 10⁹ add exponents

result: 10⁹

(10.) x^a * x^b here is the problem

= x^(a+b) add exponents

result: x^(a+b)