Answer:
[tex]\huge \boxed{x=-4}[/tex]
Step-by-step explanation:
[tex]\sf f(x)=-6x-3 \\\\\\ f(x)=21[/tex]
Applying substitution method and solving for the value of x.
[tex]\sf 21=-6x-3[/tex]
Adding 3 to both sides.
[tex]\sf 24=-6x[/tex]
Dividing both sides by -6.
[tex]\sf -4=x[/tex]
[tex]\huge\underline\bold\blue{ƛƝƧƜЄƦ}[/tex]
[tex]\large\boxed{f(x)=-129}[/tex]
Step-by-step explanation:
Given - f(x) = 21
Now we have to put the value in the given equation
f(x) = -6x-3
f(21) = -6(21) -3
= - 126 -3
= -129
Hope it helps
