a)The original price of a basketball is $ (5x+200). In a sale, the price of the
basketball is reduced by 20% to $(2x+170).Find the value of x.
b)John has two kinds of coins:$1 coins and$5 coins. One-half the number
of $1 coins is more than the number of $5 coins by60. If the total value of
the coins is $470 ,how many $1coins does John have?
thx
中一數學題急!!!!!!
2009-12-31 9:28 pm
回答 (1)
2009-12-31 9:47 pm
✔ 最佳答案
(a) (5x+200)(1-20%)=2x+170(5x+200)(0.8)=2x+170
4x+160=2x+170
2x=10
x=5
Let he has x $1 coins,x/2-60 5$ coins
Then x+5(x/2-60)=470
So 3.5x-300=470
x=220
John has 220 $1coins
Arrange the polynomial x-6x+x-8 in descending powers of x
x^3+x^2-6x-8
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