Question

a 96 - 3 . x +1 = 42

b 15x - 9x + 2x = 72

c 3^x+2 + 3^x = 10

làm bài đầy đủ

Answer 1

a,\(96-3x+1=42\)

<=> 97-3x=42

<=> 3x=55

<=>x=\(\frac{55}{3}\)

vậy.......

b, 15x-9x+2x=72

<=>8x=72

<=>x=9

vậy.....

c,\(3^{x+2}+3^x=10\)

\(\Leftrightarrow3^x\left(3^2+1\right)=10\)

\(\Leftrightarrow3^x=1\)

\(\Leftrightarrow x=0\)

vậy........

Answer 2

a 96 - 3 . x +1 = 42

96-3.x= 42-1

96 - 3 . x = 41

3.x= 96-41

3.x= 55 

x= 55 : 3 

x= \(\frac{55}{3}\)

b, 15x - 9x + 2x = 72 

x.( 15-9+2) = 72 

x8=72

x=72:8

x=9

c,  3^x+2 + 3^x = 10

  \(\Rightarrow3^x.9+3^x=10\)

\(\Rightarrow3^x.10=10\)

\(\Rightarrow3^x=1\)

\(\Rightarrow x=0\)

Answer 3

a)96-3.x+1=42

         3.x+1=96-42

          3.x+1=54

              x+1=54:3

              x+1=18

              x=18-1

              x=17