JAMB 2017 · UTME (set 2) · Q18

Simplify $4\sqrt{27} + 5\sqrt{12} - 3\sqrt{75}$ .

Worked solution (try it first)

Take out square factors: $4\sqrt{27} = 4 \times 3\sqrt3$ , which is $12\sqrt3$ .
Likewise $5\sqrt{12} = 5 \times 2\sqrt3 = 10\sqrt3$ and $3\sqrt{75} = 3 \times 5\sqrt3 = 15\sqrt3$ .
Combine: $12\sqrt3 + 10\sqrt3 - 15\sqrt3 = 7\sqrt3$ , option D.