A rectangular picture measuring 3 in. by 5 in. is surrounded by a frame with uniform width x. How do you write a quadratic function in standard form to show the combined area of the picture and frame?

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Answer 1 · 2018-06-09T05:27:19

#y=4x^2+16x+15#

Look at the diagram

enter image source here

The outer length is #=5 +2x#
The outer width is #=3 +2x#

Let the area be #=y#

Then-

#y=(5+2x)(3+2x)#

#y=15+6x+10x+4x^2#

#y=4x^2+16x+15#