Find the sum of [tex]4\sqrt{9}[/tex] and [tex]3\sqrt{10}[/tex] in simplest form. Also, determine whether the result is rational or irrational and explain your answer.



Answer :

Let's break down the problem step-by-step to find the sum of [tex]\( 4\sqrt{9} \)[/tex] and [tex]\( 3\sqrt{10} \)[/tex], and then determine whether the result is rational or irrational.

### Step 1: Calculate [tex]\( 4\sqrt{9} \)[/tex]

First, we calculate [tex]\( \sqrt{9} \)[/tex]:
[tex]\[ \sqrt{9} = 3 \][/tex]

Next, multiply by 4:
[tex]\[ 4\sqrt{9} = 4 \cdot 3 = 12 \][/tex]

### Step 2: Calculate [tex]\( 3\sqrt{10} \)[/tex]

Since [tex]\( \sqrt{10} \)[/tex] is already in its simplest radical form and is an irrational number, we can write:
[tex]\[ 3\sqrt{10} = 3 \cdot \sqrt{10} \][/tex]

### Step 3: Sum the Two Terms

Now we will sum [tex]\( 4\sqrt{9} \)[/tex] and [tex]\( 3\sqrt{10} \)[/tex]:
[tex]\[ 4\sqrt{9} + 3\sqrt{10} = 12 + 3\sqrt{10} \][/tex]

So the result in its simplest form is:
[tex]\[ 12 + 3\sqrt{10} \][/tex]

### Step 4: Determine Whether the Result is Rational or Irrational

To determine if the result is rational or irrational, recall the definitions:
- A rational number can be expressed as the quotient or fraction [tex]\(\frac{p}{q}\)[/tex] of two integers [tex]\(p\)[/tex] and [tex]\(q\)[/tex], with the denominator [tex]\(q\)[/tex] not equal to zero.
- An irrational number cannot be expressed as such a fraction and its decimal expansion is non-terminating and non-repeating.

In [tex]\( 12 + 3\sqrt{10} \)[/tex]:
- 12 is a rational number.
- [tex]\( 3\sqrt{10} \)[/tex] is an irrational number, because [tex]\(\sqrt{10}\)[/tex] is irrational and multiplying an irrational number by a non-zero rational number (in this case, 3) results in an irrational number.

The sum of a rational number (12) and an irrational number ([tex]\( 3\sqrt{10} \)[/tex]) is always irrational.

### Conclusion

The result, [tex]\( 12 + 3\sqrt{10} \)[/tex], is an irrational number. This is because it includes the term [tex]\( 3\sqrt{10} \)[/tex], which is irrational, and the sum of a rational and an irrational number is irrational.