Your answer is B. 12.
12 kids are unaccounted for after you subtract the kids that take A1, then A2, the both subjects.
Answer:
I don't understand
Step-by-step explanation:
x²-4x-5=0
The given equation is quadratic
So we can perform prime factorisation of it.
factors of -5, that add up to give -4 are -5 and 1
therefore replacing -4x by -5x+x
x²-5x+x-5=0
performing factoring by grouping,
(x²-5x)+(x-5)=0
x(x-5)+(x-5)=0
(x+1)(x-5)=0
x+1=0 and x-5=0
Answer is x=-1 and x=5