Answer:
A = 4, B = 3
Step-by-step explanation:
In order for the limit to exist and have a value of 19, the left limit and the right limit must both have that value at x=7.
left limit = 19
right limit = 19
__
4A(7)/7 +B = 19
A(7) -3B = 19
Adding 3 times the first equation to the second gives ...
3(4A +B) +(7A -3B) = 3(19) +(19)
19A = 4(19) . . . . . simplify
A = 4 . . . . . . . . divide by 19
Substituting into the first equation gives ...
4(4) +B = 19
B = 3 . . . . . . . subtract 16
A is 4, B is 3.
