牛人帮忙啊啊啊!24号考试~~SAT OG数学P970第19题!答案是E,实在不明白为啥!我选A~但错拉!
let the function f be defined by f(x)=2x-1if 1\2 f(根下t )=4what is the value of t?
A3\根号2
B7\2
C 9\2
D49\4
E 81\4