Đáp án:
Giải thích các bước giải:
`4`.
`4_2`) `(2^7. 9^3)/(6^5. 8^2)`
`=(2^7. (3^2)^3)/((2.3)^5. (2^3)^2`
`=(2^7. 3^6)/(2^5. 3^5. 2^6`
`=(2^7. 3^6)/(2^11. 3^5)`
`=(2^7. 3^5. 3)/(2^7. 2^4 .3^5`
`=3/(2^4)`
`=3/16`
`4_3`) `(6^3+3. 6^2+3^3)/-26`
`=(6^2.(6+3)+3^3)/-26`
`=(6^2. 9+3^3)/-26`
`=(6^2. 3^2+3^3)/-26`
`=(3^2.(6^2+3))/-26`
`=(3^2. 39)/-26`
`=(9.3)/-2`
`=(-27)/2`
`4_4`) `(81.(27+9^15))/(3^5+3^32)`
`=(3^4.(3^3+(3^2)^15))/(3^5+3^32`
`=(3^7+3^34)/(3^5+3^32)`
`=(3^7.(1+3^27))/(3^5.(1+3^27))`
`=(3^7)/(3^5`
`=3^2`
`=9`
`5`.
`5_2`) `x^2=81`
`=>x^2=(+-9)^2`
`=>x =+-9`
Vậy `x=+-9`.
`5_3`) `x^4=625`
`=>x^4=(+-5)^4`
`=>x=+-5`
Vậy `x=+-5`.
`5_4`) `x^2+1=17`
`=>x^2=16`
`=>x^2=(+-4)^2`
`=>x=+-4`
Vậy `x=+-4`.
`5_5`) `x^4-20=61`
`=>x^4=81`
`=>x^4=(+-3)^4`
`=>x=+-3`
Vậy `x=+-3`.