Maths Problem

[匿名]

2010-09-26 10:47 am

The sum of 3 rational numbers is -3. 2 rational numbers have the denominator 10. The product of 2 rational numbers is 7/50. The quotient of 2 rational numbers is 3. What are these 3 rational numbers?

Please work out step by step how to get the answer as I have already known the answer. My problem is : I don't know how to work it out by step.

Thx

回答 (1)

Godfrey

2010-09-26 8:44 pm

✔ 最佳答案

The sum of 3 rational numbers is -3. 2 rational numbers have the denominator 10. The product of 2 rational numbers is 7/50. The quotient of 2 rational numbers is 3. What are these 3 rational numbers?

A/10 + B/10 + E/F = -3
(The sum of 3 rational numbers is -3 and 2 rational numbers have the denominator 10. )
B x E = 7 (The product of 2 rational numbers is 7/50.)
10 x F = 50 (The product of 2 rational numbers is 7/50.)
F = 50/10 = 5
A/10 + B/10 + E/5 = -3
A/10 + B/10 + 2E/10 = -3

A + B +2E = -30
A/10)/(B/10) = A/B = 3 (The quotient of 2 rational numbers is 3. )
A = 3B
3B + B +2E = -30
4B +2E = -30
2B +E = -15
B = 7/E

14/E + E = -15
14 +E^2 = -15E
E^2 + 15E +14 = 0
(E + 14)(E +1)
E = -14 or E = -1
B = -7
A = -21

The three rational numbers are -21/10, -7/10 and -1/5

👍 0 👎 0