pls sy lupa cara ...

Mudah mudahan jelas dan dapat dipahami.

ΔA + ΔB + ΔC = 180
(3x - 5) + 95 + (x - 10) = 180
3x + x - 5 +95 -10 = 180
4x + 80 = 180
4x= 180 - 80
x = 100/4
x = 25
ΔBAC= 3x - 5
= 75-5
=70