4x² - 27x - 28 is the answer
Step-by-step explanation:
As per question,
(5x² + 23x - 7) - (x² - 4x + 21)
Removing the parentheses,
→ 5x² + 23x - 7 - x² + 4x - 21)
Now reorder and gather the like terms,
→ (5x² - x²) + (23x + 4x) + ( -7-21 )
Collecting the coefficients of like terms,
→ (5-1)x² - (23+4)x + ( -7-21 )
Calculating them now, we get,
→ 4x² - 27x - 28
So, (5x² + 23x - 7) - (x² - 4x + 21) = 4x² - 27x - 28
