Question

(4 marks)

5. Solve the following equations:
a) x+5 = 7
b) 2x - 8 = 20
c) 4x - 6x = 200
d) x+1= 5
3

Answer 1

I think:
A) x=7-5
X= 2

B) 2x=20+8
2x= 28
X= 28/2
X= 14


C) -2x= 200
X= 200/-2
C= -100

D) x=5-1
X=4

Answer 2

a) x + 5 = 7

x + 5 - 5 = 7 - 5 (Subtract 5 from both sides)

x = 2

b) 2x - 8 = 20

2x - 8 + 8 = 20 + 8 (Add 8 to each side)

2x = 28

2x/2 = 28/2 (Divide each side by 2)

x = 14

c) 4x - 6x = 200

-2x = 200

-2x/-2 = 200/-2 (Divide each side by -2)

x = -100 (Note that a negative number divided by a negative number is positive, whereas a positive number divided by a negative number is negative)

d) x + 1 = 5

x + 1 - 1 = 5 - 1 (Subtract 1 from each side)

x = 4