$1.$ Suppose a person uses the Caesar cipher to encrypt a plaintext message. The ciphertext is EVIRE, and the shift could be any value from $0$ to $25.$ Can you determine the exact plaintext?

$2.$ Suppose we use affine encryption with $(9$ x $+2)$ mod $26.$ The ciphertext is UCR. What is the plaintext?

$3.$ Suppose we use affine encryption where letter i is encrypted as $($a$$i$+$b$)$ mod $26,$ where b is chosen at random from $\{0,1,...,25\}$ and a is chosen at random from all numbers a such that gcd$($a$,26)=1.$ We denote the cipher letter for plaintext letter i as $\backslash$pi $($i$).$ Then we encrypt the message again using affine encryption with letter $\backslash$pi $($i$)$ encrypted by

$($c $\backslash$pi $($i$)+$ d$)$ mod $26,$ with c and d chosen similarly to a and b$.$ Is this method more secure than using a single affine encryption?