Respuesta :
Play A: y=15x+76
Play B: y=-x^2 +36x-4
set them equal:
15x+76=-x^2 +36x-4
80=-x^2+21x
x^2-21x+80=0
-> solve for x
for example with the quadratic equation formula or solving the square
factorized:
(x-16)(x-5)=0
so x1=5 and x2=16
insert them into y=15x+76
y1=151, y2=316
so (5,151) and (16,316) are days with equal attendance for both plays which is option C
Play B: y=-x^2 +36x-4
set them equal:
15x+76=-x^2 +36x-4
80=-x^2+21x
x^2-21x+80=0
-> solve for x
for example with the quadratic equation formula or solving the square
factorized:
(x-16)(x-5)=0
so x1=5 and x2=16
insert them into y=15x+76
y1=151, y2=316
so (5,151) and (16,316) are days with equal attendance for both plays which is option C