you can use the quadratic formula x=[-b+/-√(b^2-4ac)]/2a
now, a=10, b=9, c=-22
so,
x={-9+/-√[(9^2-4(10)(-22)]} / 2(10)
=[-9+/-√(81+880)] /20
=[-9+/-√(961)] /20
=(-9+/-31)/20
=(-9+31)/20 or =(-9-31)/20
=11/10 =2
2006-10-18 18:08:44 補充：
aiya....痴埋左tim...咁樣寫清楚d=(-9 31)/20 =11/10 or =(-9-31)/20=2
2006-10-18 18:10:17 補充：
="=........漏左個負tim.呢個岩啦!!!!!=(-9 31)/20 =11/10 or =(-9-31)/20=-2
2006-10-24 19:44:14 補充：
the answer is wrong!!!wrongwrongwrong!!!!
it should be....x=11/10 or x=-2
如果x=-11/10...咁就唔等啦...
10x^2+9x-22=-19.8
而唔係等於0...
yahoo知識有個唔好ge地方就係...choose左出黎ge answer未必係岩ge!!!