Question

2. If 4x2 + 20x + r = (2x + s)2 for all values of x,
what is the value of r-s?​

Answer 1

Answer:

just expand and equate coefficients

4x^2+20x+r = 4x^2+4sx+s^2

4s=20

s=5

r = s^2 = 25

r-s = 20