In algebra - what can the letter "d" represent? For example, what does "d" stand for in this expression "2d + 3"? *

Hurry and answer this! circle x with a radius of 6 units and circle y with a radius of 2 units are shown which steps would prove the circles similar? translate the circles so they share a common center point, and dilate circle y by a scale factor of 4. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 4. translate the circles so they share a common center point, and dilate circle y by a scale factor of 3. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 3

Solve the system of equations y= 3/2 - 1, -x+ y =-3

Ineed i been stuck on this question since yesterday