Sine and cosine. The other four functions are periodic and at some values of the input variable would be undefined.
Answer:
First, you have to form simultaneous equation for both of their ages in yerms of a and b :
b = 4a - 12 -------- ( 1 )
a + b = 28 -------- ( 2 )
Next, you will have to solve it by substituting ( 1 ) into ( 2 ) :
a + (4a - 12) = 28
5a - 12 = 28
5a = 28 + 12
5a = 40
a = 8
Then, substitute a = 8 into ( 1 ) :
b = 4(8) - 12
b = 32 - 12
b = 20
84 slices were sold individually.
364 - 84
The rest were sold as a pie
(364 - 84) ÷ 8
Answer D (But it should either be in a bracket or write as a fraction with the numerator as 364 - 84)
X=0 and y =2 if you use substitution