Question

How do you simplify 3 times the square root of 20 + 2 times the square root of 45?

Answer 1

`12sqrt5`

Explanation:

`"using the "color(blue)"law of radicals"`

`•color(white)(x)sqrt(ab)hArrsqrtaxxsqrtb`

`rArr3sqrt20+2sqrt45`

`=(3xxsqrt(4xx5))+(2xxsqrt(9xx5))`

`=(3xxsqrt4xxsqrt5)+(2xxsqrt9xxsqrt5)`

`=(3xx2xxsqrt5)+(2xx3xxsqrt5)`

`=6sqrt5+6sqrt5`

`=12sqrt5`

Answer 2

`12sqrt5`

Explanation:

`sqrt20= 2sqrt5`
`3*2sqrt5`
`6sqrt5`

`sqrt45= 3sqrt5`
`2*3sqrt5=6sqrt5`

`6sqrt5 +6sqrt5= 12sqrt5`