3x - 10 + x = 90
4x = 100
x = 25 degrees
I’m not sure which of these you meant to type so I answered both ways
B=(RT-4)/6 multiply by 6
6B= RT-4. Add 4
6B+4= RT. Divide by R
(6B+4)/R = T
Or B=RT -4/6. Multiply by 6
6B=6RT -4. Add 4
6B+4= 6RT. Divide by 6R
(6B-4)/6R = T. Reduce
(3B-2)/3R = T
