Astudent is solving the system of equations below. in which line is a mistake first made?
2x + y - 2z = 23
3x + 2y + z = 11
x - y + z = -2

line 1 z = 11 + 3x + 2y
line 2 2x + y ­- 2(11 + 3x + 2y) = 23
line 3 ­-4x ­- 3y = 45
line 4 x -­ y + (11 + 3x + 2y) = ­- 2
line 5 4x + y = - ­13
line 6 ­ -2y = 32
line 7 y = ­16, x = ¾, z = ­-11/4

Normal yağmur ile asit yağmuru arasındaki fark nedir

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

(c) the diagram shows the first three shapes of a matchsticks arrangement.first shape = 3second shape = 5third shape = 7given m represents the number of matchstick used to arrange the n'th shape.(i) write a formula to represent the relation between m and n. express m as the subjectof the formula.(ii) 19 matchsticks are used to make the p'th shape. find the value of p.