hey there! we know that these angles are complementary, which means that they will add up to be 90 degrees. now, all we have to do is algebra. if you add them, and set them equal to 90 degrees, your equations will look a bit like this.
x+6+3x-4=90
4x+2=90
4x=88
x=22 degrees
we want to find angle MFE, so we will just plug in the value of X into the given equation to find the angle measure.
22+6 degrees=28 degrees.
angle MFE=28 degrees.