Basketball was invented by the canadian james naismith in 1891.

a.) the canadian james naismith invented basketball
b.) no improvement or correction is required.
c.) basketball, which was invented by canadian james naismith,
d.) basketball, by canadian james naismith, was invented
e.) james naismith had become the inventor of basketball

often a noun phrase is just a noun or a pronoun:

people like to have money.

i am tired.

it is getting late.

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