Go to a website called desmos it’s a graphing calculator and you just type what you want graphed and it shows it
        
             
        
        
        
U subtract 4x by 5x and then you add 3 by -21 and the answer is x=18
        
             
        
        
        
Answer:
The question is not explained well, Please explain it better or take a screenshot or something
Step-by-step explanation:
 
        
             
        
        
        
First make x the subject of f(x) = 2x - 10:-
2x = f(x) + 10
x =  1/2 f(x) + 5
mow replace x by hx) and f(x) by x:-
h(x )= 1/2 x + 5