Question

a) x3 = 1.   b)    x3 = 8. c) x3 = 27. d) x3 = 64. e) x3 = 125.  f)   x3 = −1. g) x3 = −8. h) x3 = −27. i)  (−x)3 = −64. j) (−x)3 = −125. k) (−x)3 = −216. l)  (−x)3 = −343. m)(2x − 1)2 = 49. n)   (3x + 4)2 = 25. o) (2x + 7)2 = 1. p) (6 − 4x)2 = 16.

 Giải các phương trình sau :

Answer 1

`a)x^3=1`

`<=>x^3=1^3`

`<=>x=1`

`b)x^3=8`

`<=>x^3=2^3`

`<=>x=2`

`c)x^3=27`

`<=>x^3=3^3`

`<=>x=3`

`d)x^3=64`

`<=>x^3=4^3`

`<=>x=4`

`e)x^3=125`

`<=>x^3=5^3`

`<=>x=5`

`f)x^3=-1`

`<=>x^3=(-1)^3`

`<=>x=-1`

`g)x^3=-8`

`<=>x^3=(-2)^3`

`<=>x=-2`

`h)x^3=-27`

`<=>x^3=(-3)^3`

`<=>x=-3`

`i)(-x)^3=-64`

`<=>(-x)^3=(-4)^3`

`<=>-x=-4`

`<=>x=4`

`j)(-x)^3=-125`

`<=>(-x)^3=(-5)^3`

`<=>-x=-5`

`<=>x=5`

`k)(-x)^3=-216`

`<=>(-x)^3=(-6)^3`

`<=>-x=-6`

`<=>x=6`

`l)(-x)^3=-343`

`<=>(-x)^3=(-7)^3`

`<=>-x=-7`

`<=>x=7`