Se compran 30 libros a S/ 720, si se pierden 10 libros, ¿a cuánto debo vender cada uno de los restantes para ganar un total de S/180?

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

The system of equations graphed below has how many solutions?

Solve -2(4y + 6) = 52. 5 -5 8 -8 and !