\(a,5^x+5^{x+2}=650\\ \Rightarrow a,5^x+5^x.25=650\\ \Rightarrow26.5^x=650\\ \Rightarrow5^x=25\\ \Rightarrow5^x=5^2\\ \Rightarrow x=2\)

\(b,3^{x.1}+5.3^{x.1}=162\\ \Rightarrow3^x+5.3^x=162\\ \Rightarrow6.3^x=162\\ \Rightarrow3^x=27\\ \Rightarrow3^x=3^3\\ \Rightarrow x=3\)

a: \(\Leftrightarrow5^x=25\)

hay x=2

Trả lời:

\(3x+1+5\times3x+2=144\)

\(\Leftrightarrow3x+1+15x+2=144\)

\(\Leftrightarrow18x=141\)

\(\Leftrightarrow x=\frac{47}{8}\)

Vậy \(x=\frac{47}{8}\)

a) x = 12  

b) x= 27              

c) x = 3 

d) x = 2

a) 71 - (33 + x) = 26
             33 + x  = 71 - 26
             33 + x  = 45
                     x  = 45 - 33
                     x  =     12

1: \(3x^2+mx+n\)

\(=3x^2+15x+\left(m-15\right)x+5m-75-5m+75+n\)

\(3x^2+mx+n\) chia x+5 dư 27

=>-5m+75+n=27

=>-5m+n=27-75=-48

2: \(x^3+mx+n\)

\(=x^3+x^2-x^2-x+\left(m+1\right)x+m+1+n-m-1\)

\(=\left(x+1\right)\left(x^2-x+m+1\right)+n-m-1\)

\(x^3+mx+n\) chia x+1 dư 7

=>n-m-1=7

=>n=m+1+7=m+8

\(x^3+mx+n\)

\(=x^3-3x^2+3x^2-9x+\left(m+9\right)x+3m+27+n-3m-27\)

\(=\left(x-3\right)\left(x^2+3x+m+9\right)+n-3m-27\)

\(x^3+mx+n\) chia x-3 dư 5

=>n-3m-27=5

=>n=3m+27+5=3m+32

mà n=m+8

nên 3m+32=m+8

=>2m=-24

=>m=-12

n=m+8=-12+8=-4

chờ chút

mà 3x+2 là riêng x thôi hay cả 3x ậy bạn

\(B=5\cdot\left(2x-1\right)^2+4\cdot\left(x-1\right)\cdot\left(x+3\right)-2\cdot\left(5\cdot3x\right)\)

\(=5\left(4x^2-4x+1\right)+\left(4x-4\right)\cdot\left(x+3\right)-2\cdot15x\)

\(=20x^2-20x+5+4x^2+12x-4x-12-2\cdot15x\)

\(=20x^2-20x+5+4x^2+12x-4x+12-30x\)

\(=24x^2-42x-7\)

(B=5left(2x-1 ight)^2+4left(x-1 ight)left(x+3 ight)-2left(5.3x ight)=5left(4x^2-4x+1 ight)+4left(x^2-4x+3 ight)-30x=20x^2-20x+5+4x^2-16x+12-30x=24x^2-66x+17)

\(2.3^x+5.3^x.3=153\Leftrightarrow2.3^x+15.3^x=153\)

\(\Leftrightarrow17.3^x=153\Leftrightarrow3^x=9\Leftrightarrow x=2\)

\(\Leftrightarrow2.3^x+5.3.3^x=153\)

\(\Leftrightarrow17.3^x=3^2.17\)

\(\Leftrightarrow3^x=3^2\Rightarrow x=2\)