# Exam Exam

1.- Which of these equations is not a linear equation with two unknowns:

 a) x + y = -1  d) All of them are linear equations with two unknowns

2.- Select the system whose solution is x = 3 y = -2   d) None of them

3.- Decide which of these sentences is false:

 a) A system of linear equations can have 0, 1 or infinite solutions b) A system of linear equations always has a solution c) You can use the elimination method if the system has a linear equation and a quadratic one d) b and c are false

4.- Let the equation x + y = 5. Select one of the following equations to make a system with infinite solutions:

 a) x + y = 10 b) 2x + 2y = 5 c) 2x + 2y = 10 d) None of them

5.- Let the equation x + y = 5. Select one of the following equations to make a system with no solutions:

 a) x + y = 0 b) 2x + 2y = 5 c) 3x + 3y = 5 d) All of them

6.- Solve this system using the substitution method: a) x = 1; y = -3 b) x = -1; y = 3 c) x = -2; y = -1 d) None of them

7.- Solve this system using the algebraic equation method: a) x = 1; y = -1 b) x = -1; y = 1 c) x = -1; y = -1 d) None of them

8.- Solve this system using the elimination method: a) x = 0; y = 1 b) x = 0; y = -1 c) x = -1; y = 0 d) None of them

9.- I have exchanged an amount of 20 cent coins by a quantity of 1 € coins, such that I have now fewer 24 coins than before. How many 20 cent coins did I have?

 a) 24 coins b) 30 coins c) 32 coins d) 34 coins

10.- There are 420 students of ESO and Bachillerato in a secondary school. 42% of ESO students and 52% of the Bachillerato ones are girls, which makes a total of 196 girls. Calculate the number of students of ESO and Bachillerato in this school.

 a) 200 ESO students and 220 Bachillerato ones b) 221 ESO students and 199 Bachillerato ones c) 224 ESO students and 196 Bachillerato ones d) None of them