Question

What is the following product? (2 square root 7+3 square root 6)(5 square root 2+4 square root 3)

Answer 1

Answer:  The required product is $10\sqrt{14}+8\sqrt{21}+30\sqrt3+36\sqrt2.$

Step-by-step explanation:  We are given to find the following product :

P = (2 square root 7+3 square root 6)(5 square root 2+4 square root 3).

We will be using the following property of radicals :

$\sqrt a\times \sqrt b=\sqrt{ab}.$

The given product can be written and evaluated as follows :

$P\\\\=(2\sqrt7+3\sqrt6)(5\sqrt2+4\sqrt3)\\\\=2\sqrt7(5\sqrt2+4\sqrt3)+3\sqrt6(5\sqrt2+4\sqrt3)\\\\=10\sqrt{7\times2}+8\sqrt{7\times3}+15\sqrt{6\times2}+12\sqrt{6\times3}\\\\=10\sqrt{14}+8\sqrt{21}+15\times2\times\sqrt3+12\times3\sqrt2\\\\=10\sqrt{14}+8\sqrt{21}+30\sqrt3+36\sqrt2.$

Thus, the required product is $10\sqrt{14}+8\sqrt{21}+30\sqrt3+36\sqrt2.$

Answer 2

$(2\sqrt7+3\sqrt6)(5\sqrt2+4\sqrt3)\qquad\text{use distributive property}\\\\=(2\sqrt7)(5\sqrt2)+(2\sqrt7)(4\sqrt3)+(3\sqrt6)(5\sqrt2)+(3\sqrt6)(4\sqrt3)\\\\=10\sqrt{14}+8\sqrt{21}+15\sqrt{12}+12\sqrt{18}\\\\=10\sqrt{14}+8\sqrt{21}+15\sqrt{4\cdot3}+12\sqrt{9\cdot2}\\\\=10\sqrt{14}+8\sqrt{21}+15\sqrt4\cdot\sqrt3+12\sqrt9\cdot\sqrt2\\\\=10\sqrt{14}+8\sqrt{21}+(15)(2)\sqrt3+(12)(3)\sqrt2\\\\=\boxed{10\sqrt{14}+8\sqrt{21}+30\sqrt3+36\sqrt2}$