Almenn stærðfræði III - Jöfnur og jöfnuhneppi 3

 $\frac{x}{3}\ -\ \frac{x}{7}\ =\ 8$  

• x = 7

• x = 3

• x = 32

• x = 42

• x = 56

(x + 4)² = x² + 32

• x = 2

• x = 4

• x = 6

• x = 8

• x = 10

(x + 3)² = x(x + 4) + 1

• x = 6

• x = - 6

• x = 2

• x = - 2

• x = - 4

 $\frac{x}{3}\ -\ \frac{x}{9}\ =\ 10$  

• x = 45

• x = 25

• x = - 25

• x = 10

• x = - 10

X(2X - 1) - X(X + 2) - X(X - 5) = X + 1

• X = 1

• 
• X = 2

• X = 3

• X = 4

(X + 3)² - 46 = -25 + X²

• x = - 2

• x = 12

• x = 6x

• x = 2

• x = - 12

3X² + (X + 1)² - 3 = (2X - 1)²

• X = - 0,5

• X = 0,5

• X = 2

• X = - 2

• X = 4

 $\frac{x}{4}=\ \frac{10}{2}$  

•  $x\ =\ 10$  

•  $x\ =\ 20$  

•  $x\ =\ 5$  

•  $x\ =\ 15$  

•  $x\ =\ 25$  

Hvert er x-ið ?

 $x\ +\ \frac{1}{4}\ =\ 2x\ -\ \frac{1}{2}$  

•  $\frac{1}{4}$  

•  $\frac{1}{3}$  

•  $\frac{1}{2}$  

•  $\frac{3}{4}$  

•  $\frac{4}{3}$  

6x - (2x - 1) = (6x - 3x) + 4

• x = 1

• x = 2

• x = 4

• x = 3

• x = 5