Using complete sentences, analyze how the 14th, 15th, and 19th amendments of the united states constitution have influenced change in american society.

For me the most important amendment is the 19th. Women have been under the rule of men for most of the 6000 years (and maybe before) of recorded history. Men have done it simply because women and children have been dependent on the strength or cunning or food gathering abilities of men. The 19th goes a long way in rectifying that injustice. It recognized women as people and not just baby factories.

In short the 19th gave women the vote among other things <<<<

The 14th has 5 parts to it.
1. The state cannot deprive a citizen the right to defend himself in a court of law.  No right shall be taken away without due process.
2. This section states that a citizen has voting rights and these cannot be taken away. These rights are voting for president, VP, both houses of congress, and any other public election. The person voting must be 21 , male, and a citizen of the United States. You are going to have to googel the 3/5s rule. It requires comment, but not in this space. People participating in a rebellion had their voting rights stripped from them.
3. If a person has taken an oath to uphold the constitution and has engaged in a rebellion, their voting rights are taken from them. This would include senators, representatives in congress, judges etc.
4. A debt incurred in paying those who participated in putting down a rebellion, shall be considered a debt of honor and paid without question or bitterness. No payment will be made to anyone who took part in the rebellion and fought for its success, including land owners who lost money because their slaves were freed. Those debts must be born by the citizen, not the government either state or federal.
5. The government has the right to enforce these provisions by force if necessary

The whole point of this amendment was to determine who could vote, under what limiting conditions, and what reparations could be expected from the losing side, or what payment the government would or could make to those who had loses from freeing of slaves.

The act was made law in 1868. It was supposed to make things better for the slaves. In fact, it made it worse. You have to read this yourself to see how the southern states were affected by 14. It is probably the longest amendment with the most number of influences in the constitution. 

Fifteen

This has 2 parts. It is pretty straight forward.
It gave the vote to the colored (male). It prohibited restricting the vote by excluding those who had been slaves. It means you couldn't stop someone from voting just because they had been slaves.
Part 2 says that congress has the right to enforce this law. In other words the state couldn't ignore it.

This was intended (in 1870 when it was passed) to treat as equals African Americans who had formerly been slaves. In point of fact, it really didn't. Those in the south imposed poll taxes, literacy tests and other nasty bits of legislation to make sure that the colored vote and their rights were short circuited. 

Note: if you post 14 again, please offer more points. That is a huge piece of legislation which determined a great deal about how the defeated southern states were going to be treated. At least they didn't have to pay reparations.