about maths－航空百度

標題:

about maths

發問:

the sum of two numbers is 27 and their product is 180. find the two number the area of a rectangle is 88cm and its perimeter is 38 cm .find the lenght amd wirth of the rectangle the sum of square of two consecutive positive odd numbers is 202 . find the two number

最佳解答:

1) x+y = 27 xy = 180 x^2 - 27x +180 = 0 x = 12, 15 Since x, y are symmetric, the two numbers are 12, 15 2) xy = 88 2(x+y) = 38 x+y = 19 x^2 - 19x + 88 = 0 x = 8, 11 so the length is 11cm and the width is 8 cm 3) (2n-1)^2 + (2n + 1)^2 = 202 4n^2 + 1 = 101 n = 5 so the two numbers are: 9, 11

其他解答:

They are 12 and 15. The lenght is 11and wirth is 8. They are 100 and 102.