Ireally don’t understand this question.

see explanation

Step-by-step explanation:

36

Since triangle is isosceles then AB = BC

Equate the 2 sides, that is

4x - 21 = 2x - 7 ( subtract 2x from both sides )

2x - 21 = - 7 ( add 21 to both sides )

2x = 14 ( divide both sides by 2 )

x = 7, hence

AB = 2x - 7 = (2 × 7) - 7 = 14 - 7 = 7

BC = 4x - 21 = (4 × 7) - 21 = 28 - 21 = 7

AC = x - 3 = 7 - 3 = 4

37

Since the triangle is equilateral then all 3 sides are equal.

Equate any 2 sides and solve for x

6x + 1 = 3x + 10 ( subtract 3x from both sides )

3x + 1 = 10 ( subtract 1 from both sides )

3x = 9 ( divide both sides by 3 )

x = 3

HF = 6x + 1 = (6 × 3) + 1 = 18 + 1 = 19 = FG = HG

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4