1. Lisa is working with the system of equations x+2y=7 and 2x−5y=5. She multiplies the first equation by 2 and then subtracts the second equation to find 9y=9, telling her that y=1. Lisa then finds that x=5. Thinking about this procedure, Lisa wonders: A. What is the answer to Lisa's question? Explain. B. Does the answer to (a) change if we have a system of two equations in two unknowns with no solutions? What if there are infinitely many solutions? 2. Graph (Links to an external site.) the following linear system. What is the solution? y = 2x + 4 y = 3x + 2

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.

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"

How do the number line graphs of the solutions sets of -23 > x and x-23 differ?