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Solve:

Find the value of the polynomial [tex]\( 2x^3 - 3x^2 + 7 \)[/tex] at [tex]\( x = 2 \)[/tex] and [tex]\( x = -1 \)[/tex].


Sagot :

To find the value of the polynomial [tex]\(2x^3 - 3x^2 + 7\)[/tex] at [tex]\(x = 2\)[/tex] and [tex]\(x = -1\)[/tex], we need to substitute these values of [tex]\(x\)[/tex] into the polynomial and simplify. Let's go through each step-by-step.

### Evaluating the polynomial at [tex]\(x = 2\)[/tex]

1. Step 1: Substitute [tex]\(x = 2\)[/tex] into the polynomial
[tex]\[ 2(2)^3 - 3(2)^2 + 7 \][/tex]

2. Step 2: Calculate the cubed term [tex]\(2^3\)[/tex]
[tex]\[ 2^3 = 8 \implies 2 \cdot 8 = 16 \][/tex]

3. Step 3: Calculate the squared term [tex]\(2^2\)[/tex]
[tex]\[ 2^2 = 4 \implies 3 \cdot 4 = 12 \][/tex]

4. Step 4: Combine the results
[tex]\[ 16 - 12 + 7 = 11 \][/tex]

So, the value of the polynomial at [tex]\(x = 2\)[/tex] is [tex]\(11\)[/tex].

### Evaluating the polynomial at [tex]\(x = -1\)[/tex]

1. Step 1: Substitute [tex]\(x = -1\)[/tex] into the polynomial
[tex]\[ 2(-1)^3 - 3(-1)^2 + 7 \][/tex]

2. Step 2: Calculate the cubed term [tex]\((-1)^3\)[/tex]
[tex]\[ (-1)^3 = -1 \implies 2 \cdot (-1) = -2 \][/tex]

3. Step 3: Calculate the squared term [tex]\((-1)^2\)[/tex]
[tex]\[ (-1)^2 = 1 \implies 3 \cdot 1 = 3 \][/tex]

4. Step 4: Combine the results
[tex]\[ -2 - 3 + 7 = 2 \][/tex]

So, the value of the polynomial at [tex]\(x = -1\)[/tex] is [tex]\(2\)[/tex].

### Summary of Results
- The value of the polynomial [tex]\(2x^3 - 3x^2 + 7\)[/tex] at [tex]\(x = 2\)[/tex] is [tex]\(11\)[/tex].
- The value of the polynomial [tex]\(2x^3 - 3x^2 + 7\)[/tex] at [tex]\(x = -1\)[/tex] is [tex]\(2\)[/tex].

Thus, the values are:
[tex]\[ \boxed{(11, 2)} \][/tex]