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# Exam

## Exam

### Pregunta

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

#### Respuestas

a) x + y = -1

d) All of them are linear equations with two unknowns

### Pregunta

2.- Select the system whose solution is x = 3 y = -2

d) None of them

### Pregunta

3.- Decide which of these sentences is false:

#### Respuestas

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

### Pregunta

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

### Pregunta

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

### Pregunta

6.- Solve this system:

#### Respuestas

a) x = 1; y = -3

b) x = -1; y = 3

c) x = -2; y = -1

d) None of them

### Pregunta

7.- Solve this system:

#### Respuestas

a) x = 1; y = -1

b) x = -1; y = 1

c) x = -1; y = -1

d) None of them

### Pregunta

8.- Solve this system:

a) x = 0; y = 1

b) x = 0; y = -1

c) x = -1; y = 0

d) None of them

### Pregunta

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

### Pregunta

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.

#### Respuestas

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