Precalculus Examples

$\frac{lim_{x \to 8} 6 x^{4} - 5 x^{3} - 2 x + 1}{3 x^{4} - 2 x - 7}$

Step 1

Split the limit using the Sum of Limits Rule on the limit as $x$ approaches $8$ .

$\frac{lim_{x \to 8} 6 x^{4} - lim_{x \to 8} 5 x^{3} - lim_{x \to 8} 2 x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 2

Move the term $6$ outside of the limit because it is constant with respect to $x$ .

$\frac{6 lim_{x \to 8} x^{4} - lim_{x \to 8} 5 x^{3} - lim_{x \to 8} 2 x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 3

Move the exponent $4$ from $x^{4}$ outside the limit using the Limits Power Rule.

$\frac{6 {(lim_{x \to 8} x)}^{4} - lim_{x \to 8} 5 x^{3} - lim_{x \to 8} 2 x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 4

Move the term $5$ outside of the limit because it is constant with respect to $x$ .

$\frac{6 {(lim_{x \to 8} x)}^{4} - 5 lim_{x \to 8} x^{3} - lim_{x \to 8} 2 x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 5

Move the exponent $3$ from $x^{3}$ outside the limit using the Limits Power Rule.

$\frac{6 {(lim_{x \to 8} x)}^{4} - 5 {(lim_{x \to 8} x)}^{3} - lim_{x \to 8} 2 x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 6

Move the term $2$ outside of the limit because it is constant with respect to $x$ .

$\frac{6 {(lim_{x \to 8} x)}^{4} - 5 {(lim_{x \to 8} x)}^{3} - 2 lim_{x \to 8} x + lim_{x \to 8} 1}{3 x^{4} - 2 x - 7}$

Step 7

Evaluate the limit of $1$ which is constant as $x$ approaches $8$ .

$\frac{6 {(lim_{x \to 8} x)}^{4} - 5 {(lim_{x \to 8} x)}^{3} - 2 lim_{x \to 8} x + 1}{3 x^{4} - 2 x - 7}$

Step 8

Evaluate the limits by plugging in $8$ for all occurrences of $x$ .

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Step 8.1

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{6 \cdot 8^{4} - 5 {(lim_{x \to 8} x)}^{3} - 2 lim_{x \to 8} x + 1}{3 x^{4} - 2 x - 7}$

Step 8.2

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{6 \cdot 8^{4} - 5 \cdot 8^{3} - 2 lim_{x \to 8} x + 1}{3 x^{4} - 2 x - 7}$

Step 8.3

Evaluate the limit of $x$ by plugging in $8$ for $x$ .

$\frac{6 \cdot 8^{4} - 5 \cdot 8^{3} - 2 \cdot 8 + 1}{3 x^{4} - 2 x - 7}$

Step 9

Simplify the numerator.

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Step 9.1

Raise $8$ to the power of $4$ .

$\frac{6 \cdot 4096 - 5 \cdot 8^{3} - 2 \cdot 8 + 1}{3 x^{4} - 2 x - 7}$

Step 9.2

Multiply $6$ by $4096$ .

$\frac{24576 - 5 \cdot 8^{3} - 2 \cdot 8 + 1}{3 x^{4} - 2 x - 7}$

Step 9.3

Raise $8$ to the power of $3$ .

$\frac{24576 - 5 \cdot 512 - 2 \cdot 8 + 1}{3 x^{4} - 2 x - 7}$

Step 9.4

Multiply $- 5$ by $512$ .

$\frac{24576 - 2560 - 2 \cdot 8 + 1}{3 x^{4} - 2 x - 7}$

Step 9.5

Multiply $- 2$ by $8$ .

$\frac{24576 - 2560 - 16 + 1}{3 x^{4} - 2 x - 7}$

Step 9.6

Subtract $2560$ from $24576$ .

$\frac{22016 - 16 + 1}{3 x^{4} - 2 x - 7}$

Step 9.7

Subtract $16$ from $22016$ .

$\frac{22000 + 1}{3 x^{4} - 2 x - 7}$

Step 9.8

Add $22000$ and $1$ .

$\frac{22001}{3 x^{4} - 2 x - 7}$