### Instruction: Evaluate $3x^2+5x-1$ if $x=7$.### Response: I want to find the value of the expression when x is 7, so I will substitute 7 for x in the expression and simplify.
I can use parentheses to help me keep track of the substitution: $3(7)^2+5(7)-1$.
Next, I will follow the order of operations and evaluate the exponents first: $3(49)+5(7)-1$.
Then, I will multiply: $147+35-1$.
Finally, I will add and subtract from left to right: $182-1=181$.