Question

Evaluate the following expression when x = 15.
7x5 + 3x - 2

Answer 1

To evaluate the expression \(7x^5 + 3x - 2\) when \(x = 15\), we start by substituting \(15\) for \(x\).

1. Calculate \(x^5\):
\[
15^5 = 759375
\]

2. Now substitute \(15\) into the expression:
\[
7(15^5) + 3(15) - 2
\]
\[
= 7(759375) + 3(15) - 2
\]

3. Calculate \(7(759375)\):
\[
7 \times 759375 = 5315625
\]

4. Calculate \(3(15)\):
\[
3 \times 15 = 45
\]

5. Now combine these results into the expression:
\[
5315625 + 45 - 2
\]

6. First, add \(5315625 + 45\):
\[
5315625 + 45 = 5315670
\]

7. Then subtract \(2\):
\[
5315670 - 2 = 5315668
\]

Therefore, the result of the expression \(7x^5 + 3x - 2\) when \(x = 15\) is \(\boxed{5315668}\).