Answer :

The values of x and the side length are as follows:

a. x = 6 ; RS = 15; ST = 19; RT = 34;

b. x = 5 ; RS = 20; ST = 1; RT = 21;

How to write equation in terms of x?

Point S is between R and T.

Therefore, the equation in terms of x can be represented as follows:

RT = RS + ST

a.  

RS = 4x - 9

ST = 19

RT = 8x - 14

Hence,

8x - 14 = 4x - 9 + 19

8x - 14 = 4x - 9 + 19

8x - 14 = 4x + 10

8x - 4x = 10 + 14

4x = 24

x = 24 / 4

x = 6

RS = 4x - 9 = 4(6)  - 9  = 24 - 9 = 15

ST = 19

RT = 8x - 14 = 8(6) - 14 = 48 - 14 = 34

b.

RS = 2x + 10

ST = x - 4

RT = 21

Therefore,

21 = 2x + 10 + x - 4

21 = 3x + 6

21 - 6 = 3x

15 = 3x

divide both sides by 3

x = 15 / 3

x = 5

RS = 2x + 10 = 2(5) + 10 = 10 + 10 = 20

ST = x - 4 = 5 - 4 = 1

RT = 21

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