Answer :
Answer: The required value of x is -4.
Step-by-step explanation: We are given to find the value of x if :
[tex]f(x)=2x+7~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\\\\f(x)=-1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)[/tex]
Since both the equations (i) and (ii) are the values of x, so comparing the equations, we get
[tex]2x+7=-1\\\\\Rightarrow 2x=-1-7\\\\\Rightarrow 2x=-8\\\\\Rightarrow x=-\dfrac{8}{2}\\\\\Rightarrow x=-4.[/tex]
Thus, the required value of x is -4.