The problem is asking me to combine like terms to create an equivalent expressions and the problem is 3.4-2.8d+2.8d-1.3 and i put 5.6d+2.1 but its telling me my answer includes a wrong variable letter can someone please help me out

Find the length of cu, the triangles are similar.

What is the solution to the equation in the & show work i’m very

Amodel rocket is launched from a roof into a large field. the path of the rocket can be modeled by the equation y = -0.04x^2 + 8.6x + 4.8, where x is the horizontal distance, in meters, from the starting point on the roof and y is the height, in meters, of the rocket above the ground. how far horizontally from its starting point will the rocket land? a. 0.56 m b. 215.56 m c. 431.11 m d. 215.74 m