kx^2-18x+8=0,求kkx^2-18x+8=0文字表述：k乘以x的平方减去18x加8等于0,求k=?原题：kx^2-18x+8=0hasonesolutiontwiceasbigastheother，whatisthevalueof不知道原句确切意思是什么~

Question

kx^2-18x+8=0,求k
kx^2-18x+8=0
文字表述：k乘以x的平方减去18x加8等于0,求k=?
原题：kx^2-18x+8=0 has one solution twice as big as the other，what is the value of 不知道原句确切意思是什么~

Answer 1

k为9
设解为x,2x(因为one solution twice as big as the other）
则,根据韦达定理得
3x=18/k
2x^2=8/k
解得
k=9