How many blue pens were there to start with?

What is the value of x? enter your answer in the box. photo attached.

Give the functions f(x) = |x + 2| - 3, what is the domain? a, b,c, or d all real numbers x > 2 x < -2 all real numbers and x cannot equal to 2

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?