Answer :

Certainly! Let's evaluate the definite integral

[tex]\[ \int_1^2 \left( \frac{x^2}{3} + 7 \right) \, dx \][/tex]

We will break this down into a few steps to find the exact value.

### Step 1: Split the Integral
First, we can split the integral into two separate integrals:

[tex]\[ \int_1^2 \left( \frac{x^2}{3} + 7 \right) dx = \int_1^2 \frac{x^2}{3} \, dx + \int_1^2 7 \, dx \][/tex]

### Step 2: Evaluate Each Integral Separately

#### Integral 1: [tex]\(\int_1^2 \frac{x^2}{3} \, dx\)[/tex]

We can factor out [tex]\(\frac{1}{3}\)[/tex]:

[tex]\[ \int_1^2 \frac{x^2}{3} \, dx = \frac{1}{3} \int_1^2 x^2 \, dx \][/tex]

Now, we find the antiderivative of [tex]\(x^2\)[/tex], which is [tex]\(\frac{x^3}{3}\)[/tex]:

[tex]\[ \frac{1}{3} \left[ \frac{x^3}{3} \right]_1^2 = \frac{1}{3} \left( \frac{2^3}{3} - \frac{1^3}{3} \right) = \frac{1}{3} \left( \frac{8}{3} - \frac{1}{3} \right) = \frac{1}{3} \cdot \frac{7}{3} = \frac{7}{9} \][/tex]

#### Integral 2: [tex]\(\int_1^2 7 \, dx\)[/tex]

For this integral, we simply integrate the constant 7:

[tex]\[ \int_1^2 7 \, dx = 7 \left[ x \right]_1^2 = 7 (2 - 1) = 7 (1) = 7 \][/tex]

### Step 3: Combine the Results

Finally, we add the results of the two integrals together:

[tex]\[ \frac{7}{9} + 7 = \frac{7}{9} + \frac{63}{9} = \frac{7 + 63}{9} = \frac{70}{9} \][/tex]

Thus, the exact value of the definite integral

[tex]\[ \int_1^2 \left( \frac{x^2}{3} + 7 \right) dx \][/tex]

is

[tex]\[ \boxed{\frac{70}{9}} \][/tex]

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