Answer:
21440
Step-by-step explanation:
<h2>
Simplify:</h2>
Start by multiplying 7x³ by x² and -5.
- 7x⁵ - 35x³ + (8x² - 3)(x² - 5)
Multiply 8x² by x² and -5.
- 7x⁵ - 35x³ + 8x⁴ - 40x² + (-3)(x² - 5)
Multiply -3 by x² and -5.
- 7x⁵ - 35x³ + 8x⁴ - 40x² -3x² + 15
Combine like terms together.
- 7x⁵ - 35x³ + 8x⁴ - 43x² + 15
Rearrange the terms in descending power order.
- 7x⁵ + 8x⁴ - 35x³ - 43x² + 15
<h2>Verify (I): </h2>
Substitute x = 5 into the above polynomial.
- 7(5)⁵ + 8(5)⁴ - 35(5)³ - 43(5)² + 15
Evaluate the exponents first.
- 7(3125) + 8(625) - 35(125) - 43(25) + 15
Multiply the terms together.
- 21875 + 5000 - 4375 - 1075 + 15
Combine the terms together.
This is the answer when substituting x = 5 into the simplified expression.
<h2>
Verify (II):</h2>
Substitute x = 5 into the expression.
- [7(5)³ + 8(5)² - 3][(5)² - 5]
Evaluate the exponents first.
- [7(125) + 8(25) - 3][(25) - 5]
Multiply the terms in the first bracket next.
Evaluate the expressions inside the brackets.
Multiply these two terms together.
This is the answer when substituting x = 5 into the original (unsimplified) expression.
