Question

- Three people examine the system of linear equations shown.

y=- 2 x - 4
y=- 2 x +4
Jeremy says there is exactly one solution. Wanda says there is no solution. Barry says
there are infinitely many solutions.
Which student is correct? Explain how you know.

Answer 1

there are no solutions as the two straight lines represented by the two equations are parallel, so they have no point in common

Explanation:

general equation of a straight line: ax + by + c = 0

the slope (or raise) of a straight line m is equal to -a/b (b=1 a=-2 in this exercise as the equation is 1y=-2x - 4)

so m1 = -2/1 = -1/2

and m2 = -2/1 = -1/2

there is also a geometrical explanation, but I am not sure if it could be too complex