Math: c362c210

ID: c362c210

(SAT Suite Question Bank > Find Questions > Assessment: SAT + Test: Math + Domain: Algebra)

Comment: Isolate one variable rather than focusing on both simultaneously.

Method 1: The SAT loves these graph questions that track two unknowns at the same time, whether it is a question on jobs, food, or plants. (I have seen all three.) The game is the same each time. Here, if the question asks about the price, in dollars, of 1 cornflower, then set the other unknown, wallflowers, to 0 to figure out the cost of cornflowers. The graph shows an x-intercept of 16, so someone could buy 16 cornflowers and 0 wallflowers for exactly $24.00. The mental math process might look like the following:

$24.00/16 cornflowers

$3.00/2 cornflowers

$1.50/1 cornflower

The answer is 1.5, although 3/2 is also acceptable.

Method 2: There is no need to graph something that is provided. The only use for Desmos here is to calculate.

Method 3: You could model the line for practice and then solve algebraically, even if doing so would only recreate what the graph shows you.

y = mx + b

y = mx + (12) (from the y-intercept of the graph)

Now, pick any two points that lie on the line in the graph. For the sake of illustration, I will choose (4, 9) and (8, 6).

m = ((6) - (9))/((8) - (4))

m = (-3)/(4)

m = -3/4

y = -(3/4)x + 12

Since cornflowers are modeled on the x-axis in the graph, plug in 0 for wallflowers (on the y-axis) to isolate the cornflowers.

(0) = -(3/4)x + 12

-12 = -(3/4)x

16 = x

Keep in mind, this value corresponds to the number of cornflowers someone could buy for $24.00. Thus, the price for 1 cornflower will be $24.00/16, or, once again, $1.50, which should be entered as 1.5 or 3/2.