Question

4 √(20) + 12 √(125) - 15 √(45)

Answer 1

Step-by-step explanation:

4√20 +12√125 -15√45

4√(4×5) + 12√(25×5) - 15√(9×5)

4×2√5 + 12×5√5 - 15×3√5

8√5 + 60√5 - 45√5

68√5 - 45√5

23√5

Answer 2

Step-by-step explanation:

$4 \sqrt{20} + 12 \sqrt{125} - 15 \sqrt{45 } \\ = 4 \sqrt{4 \times 5} + 12 \sqrt{25 \times 5} - 15 \sqrt{9 \times 5} \\ \\ = (4 \times 2 \sqrt{5)} + (12 \times 5\sqrt{5} ) - (15 \times 3 \sqrt{5} ) \\ = 8 \sqrt{5} + 60 \sqrt{5} - 45 \sqrt{5} \\ = 23 \sqrt{5}$