Løsning af ligninger og matematiske opgaver

Opg 1,10

X + 12 = 4x – 9

x-4x +12 = -9

-3x + 12 = -9

-3x = -12-9

-3x= -21

X = 7

5y-4=y+20

5y-y-4=20

4y = 20+4

4y = 24

Y = 6

3a + 2 = a – 10

3a – a + 2 = 10

2a = 10+2

2a = 12

A = 6

Opg 1,11

5(2y – 4) = 7y + 1

5 * 2y -4 = 7y +1

10y – 20 = 7y +1

10y -7y = 20+1

3y = 21

Y= 7

(4c + 5) 4 = 8c + 44

16c + 20 = 8c + 44

16c – 8c = - 20 + 44

8c = 24

C = 3

(3x + 2) 5 = 5x + 10

15x + 10 = 5x + 10

15x – 5x = -10 + 10

10x = 0

X = 1

Opg 1,12

3x – 4 = x + 10

3*7 – 4 = 17

7+10 = 17

2 (5 + 2v) = 8v + 2

10 + 4v = 8v + 2

4v – 8v = 10-2

-4v = 8

V = -2

(3x – 4) 2 = 4x – 4

6x – 8 = 4x – 4