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4分之7rst+2rs-6str-2分之sr

= 7rst/4 + 4rs/2 - 24rst/4 - sr/2

= -17rst/4 + 3rs/2

係唔係打錯問題,計唔到野架wo

If each side of a square is increased by 5cm,the new perimeter is 66cm.Find the original length of the side of the square.

let x cm be the original length of the side of the square,

4(x+5) = 66

x +5 =16.5

x = 11.5

so, the original length of the side of the square is 11.5cm.

Henry has $200.He buys a reference book for $30,and some novels at $18 each. If he still has$26 after buying the books, how many novels does he buy?

Let x be the number of novels he buy,

30 + 18x + 26 = 200

18x = 144

x = 8

so,he buys 8 novels.

Ken's age is half of his father's age now. Eight year later, Ken's father will be 60 years old. Find the present age of Ken.

Let x be the present age of Ken,

2x + 8 = 60

2x = 52

x = 26

so,Ken is 26 years old now.

1) 7rst/4+2rs-6str-sr/2
=-17rst/4+3rs/2
=6rs/4-17rst/4
=1/4rs(6-17t)

2)let x be the original length of side of the square.
(x+5)*4=66
4x+20=66
4x=46
x=11.5cm

3)let x be the no. of novels Henry's buy
30+18x+26=200
18x=144
x=8

4)let x be the present age of Ken.
2x+8=60
2x=52
x=26