Question

Billy graphed the system of linear equations to find an approximate solution.

y = A system of equations. y equals negative StartFraction 7 over 4 EndFraction x plus StartFraction 5 over 2 EndFraction. y equals StartFraction 3 over 4 EndFraction x minus 3.x +
y = x – 3

A coordinate grid with 2 lines. The first line is labeled y equals negative StartFraction 7 over 4 EndFraction x plus StartFraction 5 over 2 EndFraction and passes through the (0, 2.5) and (2.2, negative 1.4). The second line is labeled y equals StartFraction 3 over 4 EndFraction x minus 3 and passes through (0, negative 3, 0.14) and (2.2, negative 1.4)
Which points are possible approximations for this system? Select two options.

(1.9, 2.5)
(2.2, –1.4)
(2.2, –1.35)
(1.9, 2.2)
(1.9, 1.5)

Answer 1

(2.2, –1.4) and (2.2, –1.35)

Reason: both lines meet at x = 2.2. Plugging x = 2.2 into y = -7/4 x + 5/2 and y = 3/4 x - 3 gives y = -1.35, so (2.2, -1.35) is the exact intersection and (2.2, -1.4) is a reasonable graphing approximation.