Toán Lớp 6: (2x+1) mũ 2=625 5 mũ x +5 mũ x+1=750

Question

Toán Lớp 6:  (2x+1) mũ 2=625 5 mũ x +5 mũ x+1=750

minhtuquynh · Answer

Giải đáp:       Lời giải và giải thích chi tiết:   $a)(2x+1)^2=625&hArr;(2x+1)^2=25^2&hArr;2x+1=25   &hArr;2x=25-1&hArr;2x=24&hArr; x= dfrac{24}{2}&rArr;x=12   b)5^{x+1} + 5^{x+2}=750&hArr;5^x .5^1+5^x.5^2=750   &hArr;5^x.(5+25)=750&hArr;5^x.30=750&hArr;5^x= dfrac{750}{30}   &hArr;5^x=25&hArr;5^x=5^2&rArr;x=2    color{red}{ mathscr{X_{ textit{in hay nhất}}}}$

lanngocha · Answer

(2x+1)^2=625     &hArr;(2x+1)^2=25^2     &hArr;2x+1=25     &hArr;2x=25-1     &hArr;2x=24     &hArr; x=24:2     &rArr;x=12     vậy x = 12      $5^{x+5}$+$5^{x+1}$=750     &hArr;$5^{x+5}$ +$5^{x+1}$=750     &hArr;$5^{x+5}$ +$5^{x+1}$ =750     &hArr;5^x .5^5+5^x.5^1=750     &hArr;5^x.(3125+5)=750     &hArr;5^x.3130=750     &rArr; ko c&oacute; kết quả     nếu l&agrave; c&acirc;u của mik      $5^{x+1}$+$5^{x+2}$=750     &hArr;$5^{x+1}$ +$5^{x+2}$=750     &hArr;$5^{x+1}$ +$5^{x+2}$ =750     &hArr;5^x .5^1+5^x.5^2=750     &hArr;5^x.(5+25)=750     &hArr;5^x.30=750     &hArr;5^x=750:30     &hArr;5^x=25     &hArr;5^x=5^2     &rArr;x=2     vậy x=2     $#ng&aacute;o$