Answer:
-2x² + 90x + 500
Step-by-step explanation:
Use FOIL method
Area of rectangle = length * width
= (50 - x)(2x + 10)
= 50*(2x) + 50*10 + (-x)*2x + (-x)*10
= 100x + 500 - 2x² - 10x
= -2x² + 100x - 10x + 500 {Combine like terms}
= -2x² + 90x + 500
