What value of y satisfies the equation 3y+1.3=4

What is the value of x when x + 7 = 21?

Suppose i pick a jelly bean at random from a box containing one red and eleven blue ones. i record the color and put the jelly bean back in the box. if i do this three times, what is the probability of getting a blue jelly bean each time? (round your answer to three decimal places.)

The area of a circle is equal to 1 dm². find the radius of the circle.