Answer: 13
Step-by-step explanation:
Equilateral triangle means that all sides are equal
Soo
3x + 1 must be equal to 5x - 9
3x + 1 = 5x - 9
-2x = -10
x = 5
Substitute x as 5 into either side value
3(5) + 1 = 15 + 1 = 16
So, all sides equal 16
Which means that y + 3 also equals 16
y + 3 = 16
y = 13
