Answer:
step 2
Step-by-step explanation:
Given
(2x - 3)(5x² - 2x + 7)
2x(5x² - 2x + 7) = 10x³ - 4x² + 14x ← step 1 is correct
- 3(5x² - 2x + 7) = - 15x² + 6x - 21 ← step 2 in her working is incorrect
Adding the results from step 1 and step 2
10x³ - 4x² + 14x - 15x² + 6x - 21 ← collect like terms
= 10x³ - 19x² + 20x - 21