Question

1. A rectangle has side lengths of 3x2 + 5x - 1 and -7x+1. Which of the following expressions represents the area of the rectangle?

a. 3x²-21
b. 3x² - 35x-1
c. -21x³ - 38x²- 2x - 1
d. -21x³ - 32x² + 12x - 1

please help​

Answer 1

21x³-42x²+12x-1

[area of rectangle =length ×breadth

=(3x2 + 5x - 1)(-7x+1)

=3x²(-7x+1)+5x(-7x+1)-1(-7x+1)

=-21x³+3x²-45x²+5x+7x-1

=-21x³-42x²+12x-1