Alex stocks up for winter. he buys 36 cans of vegetables. he pays 80 cents per can for tomatoes and 40 cents per can for corn, for a total cost of $20.8. how many tomatoes does he buy? ?

Let tomatoes be as x and corn be as y.
Total cans is 36 cans.
$20.8 = 2080 cents

1. x + y = 36
2. 80x + 40y = 2080

From equation 1, we get
y = 36 - x

Substitute into equation 2,
80x + 40(36 - x) = 2080
80x + 1440 - 40x = 2080
40x = 2080 - 1440
x = 640 ÷ 40
x = 16

x + y = 36
16 + y = 36
y = 36 - 16
y = 20

Alex does buy 16 tomatoes.

1.17+3.99a. you combine the terms with a to create 3.99 and the 1.17 stays because it has no like terms or a variable

Idon't see any graph, however the graph of the function : f(x) = x²-2x+3 is a parabola: 1) open upward (since a> 0)2) it intersects y-axis in 3 (y=3)3) its axis of symmetry is x = +1 ( -b/2a)4) it's minimum is y = -2, so its vertex is (1,-2)5) it doesn't intersect the x-axis since discriminant < 0