Y =ax² + bx +c
1) Point (0,7)
7 = a*0² +b*0 +c
c = 7
y=ax² + bx + 7
2) Point (1,4)
4=a*1² + b*1 + 7, ----> 4 = a +b + 7, ------>
a+b= - 3
3) Point (2, 5)
5=a*2² + b*2 + 7, ----> 5=4a+2b +7,---> -2=4a+2b, ---->
-1=2a + b
4)
a+b= - 3, ----> b= -3 - a (substitute in the second equation)
2a+b= -1
2a - 3 - a = -1, ----> a - 3 = -1,
a =2
5) a+b= - 3
2 + b = -3
b = -5
y=2x² - 5x + 7
X+y=44
x=5/6y
x+y=44
5/6y+y=44
11/6y=44
11y=264
y=24
x=5/6y=(5/6)*24=20
Answers: numbers are 20, 24
your answer is d because the formula is Ax+By=C
10.99x = 3.99x + 280
7x = 280
x = 40
They must sell 40 T-shirts to break even
n - 12 = -9
Add 12 to both sides to isolate the variable n.
n = -9 + 12
n = 3
B) n = 3