Part A: Given the equation : 5 + x - 12 = x - 7
Solve the equation,
[tex]\begin{gathered} 5+x-12=x-7 \\ \text{take left hand side of equation,} \\ \text{LHS}=5+x-12 \\ =x-7 \\ =\text{RHS} \end{gathered}[/tex]Hence, it proves that 5 + x - 12 = x - 7
Part B: for x=-4
[tex]\begin{gathered} \text{LHS}=5+x-12 \\ =5-4-12 \\ =-11 \\ \text{Take RHS,} \\ \text{RHS}=x-7 \\ =-4-7-11 \\ \text{hence, LHS=RHS for x=-4} \end{gathered}[/tex]For x=0,
[tex]\begin{gathered} \text{LHS}=5+x-12 \\ =5+0-12 \\ =-7 \\ \text{RHS}=x-7 \\ =0-7 \\ =-7 \\ \text{hence, LHS=RHS for x=0} \end{gathered}[/tex]For x=5,
[tex]\begin{gathered} \text{LHS}=5+x-12 \\ =5+5-12 \\ =-2 \\ \text{RHS}=x-7 \\ =5-7 \\ =-2 \\ \text{Hence, LHS=RHS for x=5} \end{gathered}[/tex]Answer: The euation is : 5 + x - 12 = x - 7
The values of x =-4,0,5 all satisfies the given equation.