a) x = 9
b) x = 2
Explanation:[tex]a)\text{ }3x=x+x+9[/tex]
collect like terms:
[tex]\begin{gathered} 3x=2x+9 \\ \text{subtract 2x from both sides:} \\ 3x\text{ - 2x = 2x - 2x + 9} \\ x\text{ =0 + 9} \\ x\text{ = 9} \end{gathered}[/tex]
[tex]\begin{gathered} 3x\text{ - 2x = 2x - 2x + 9} \\ x\text{ = 0 + 9} \\ x\text{ = 9} \end{gathered}[/tex][tex]\begin{gathered} \text{check: substitute the value of x in the equation} \\ 3(9)\text{ = 9 + 9 + 9} \\ 27\text{ = 27} \\ \text{left hand side = right hand side} \\ \text{Hence, it is correct} \end{gathered}[/tex][tex]\begin{gathered} b)\text{ 3x + x = x+ 6} \\ \text{collect like terms:} \\ 4x\text{ = x + 6} \\ \text{subtract x from both sides:} \\ 4x\text{ - x = 6} \\ 3x\text{ = 6} \end{gathered}[/tex][tex]\begin{gathered} \text{divide through by 3:} \\ \frac{3x}{3}=\text{ }\frac{6}{3} \\ x\text{ = 2} \end{gathered}[/tex]
check: replace x with 2
3(2) + 2 = 2 + 6
6 +2 = 2+ 6
8 = 8
Hence, it is correct
