Question

Please can someone answer this question, I never understand these and would like to know how to do them... QUESTION ATTACHED

Answer 1

sqrt (2) * sqrt(45) + sqrt (2) * sqrt (80)

45 = 9 *5 "9" is a perfect square so

sqrt (45) = 3 * sqrt (5) * sqrt (2)

sqrt (2) * sqrt (80)

80 = 16 * 5 "16" is a perfect square so

sqrt (2) * sqrt (80) = sqrt (2) * 4 * sqrt(5)

Adding both answers we get

3 * sqrt (5) * sqrt (2) = 3 * sqrt(10)

PLUS

4 * sqrt (10)

which equals

7 * sqrt (10)

SO, the value of a is 7

Explanation: