Answer: If f(x)=0 then x is 0. Good luck!
Step-by-step explanation: GIVE ME BRAINLY A VOTE AND A THANKS BYE
Answer: 10
<u>Step-by-step explanation:</u>
varies directly means: 
Step 1: solve for k ⇒ 
Step 2: plug in the given value and k to solve for the missing value: 
42(5) = 21(x)

2(5) = x
10 = x
Factor out the GCF, which is 4.... 4(4a+3b)
Answer
It’s x= -4 for sure