Question

判断下列时候有零点,如有,请求出.(1)f(x)=x³+1 (2)x²+4x-12/x-2

Answer 1

1、x³ + 1 = 0

x³ = - 1 ,x = - 1

2、(x²+4x - 12) / (x-2) = 0

(x-2)(x+6) / (x-2) = 0

x+6 = 0

x = - 6

3、3^(x+1) - 7 = 0

3^(x+1) = 7

x+1 = log3 (7)

x = log3 (7) - 1

4、log5 (2x-3) = 0

2x - 3 = 1

x = 2