Help, will give brainliest

x = 8.94 inches

Step-by-step explanation:

Since it is already given that the area of the painting is 400 in² and the fact that area is length times width, we can make an equation and solve for x:

A=LW

400=(4x+9)(x)

400=4x^2+9x

0=4x^2+9x-400

Use the quadratic formula:

x=[-9±√(9²-4(4)(-400))]/2(4)

x=[-9±√(81+6400)]/8

x=[-9±√(6481)]/8

x = [-9+√(6481)]/8 = 8.938082281 = 8.94

x = [-9-√(6481)]/8 = -11.18808228 = -11.19

Since distance can only be positive, we will choose 8.94 as the correct solution. Therefore, x = 8.94 inches is the correct answer.