Abook store is having a 30% off sale. dairy of a wimpy kid books are now 6.30 each. what was the original price of the books

 " $ 9.00 " .

The original price of the each book was:  " $ 9.00 " .

Let "x" = the "original price" (in "dollars").

30% of "x"  = (0.30)x = (0.3)x .

"x − (0.3x) = 6.30 ; 

" 1x − 0.3x = 6.30 " ; 

  " (0.7)x = 6.3 " ; 

Divide each side of the equation by "(0.7)" ;
  to isolate "x" on one side of the equation; & to solve for "x" ;

 
  " (0.7)x / (0.7) = 6.3 / (0.7) " ;

to get:

 →  x = 9 (dollars) 

 " $ 9.00 " .

The original price of each books was:  " $ 9.00 " .

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.