Is many books has been written about the civil rights movement a strong thesis statement

yes and no. Try to make it more specific. see explaination

Explanation:

Instead of "many books has been written about the civil rights movement", put "The Civil Rights movement had many events that led many books to be written on the topic."

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4

- "chilles is sad and angry because hector, the trojan leader, killed his best friend patroclus. he seems angry with himself because he didn't or protect patroclus against the trojans."