Use calculator - answer correct to 3 places.

a. 3sqrt17 + 2sqrt15 / 5sqrt7 = 10.644

b. 2sqrt11 - 3sqrt2 + 15sqrt10 + 5sqrt5 = 61.005

c. 4.3sqrt6.9 / 1.7sqrt57 = 50.163

Can someone check my answers? I keep getting the feeling these are not the right answers. Thank you.

a. is wrong. You need parentheses to clarify the numerator of the fraction. Is it 2sqrt15 or (3sqrt17 + 2sqrt15) ?

Both possibilities do not agree with your answer.

b. is correct
c. is wrong. It is clearly less than one.