if RS=8y+4,

,,ST=4y+8 and
RT=15y-9 find the value of y

RS + ST = RT

(8y + 4) + (4y + 8) = 15y - 9
12y + 12 = 15y - 9
21 = 3y
y = 7

If RS + ST= RT then

8y+4+4y+8=15y-9
solve for y

Y=7

To find the value of y, we can use the information given about the lengths of the line segments RS, ST, and RT. We will use the fact that the sum of the lengths of two line segments is equal to the length of the third segment in a triangle.

Given:
RS = 8y + 4
ST = 4y + 8
RT = 15y - 9

In a triangle, the sum of the lengths of two sides is always greater than the length of the third side. Therefore, we can write the following equations:
RS + ST > RT
RS + RT > ST
ST + RT > RS

Now, substitute the given values into the equations:
(8y + 4) + (4y + 8) > 15y - 9
12y + 12 > 15y - 9

Combine like terms:
12y + 12 > 15y - 9
-3y > -21

Divide both sides of the equation by -3 (note that we reverse the inequality sign since we are dividing by a negative number):
y < -21 / -3
y < 7

Therefore, the value of y is less than 7.

Note: It's possible that there may be additional constraints or information provided that would allow us to find the specific value of y. However, based on the given information, we can only determine that y is less than 7.