Answer:
-7
Explanation:
The two lines intersect at the point (6,10), so this point belongs to both lines. This means that if we use the value of x = 6 in the lines, we will find y = 10
So we can use this point to find the values of b and m:
y = mx + 4
10 = 6m + 4
6m = 6
m = 1
y = 3x + b
10 = 3*6 + b
b = 10 - 18 = -8
So the value of b + m is -8 + 1 = -7