Question

Heather was asked to graph 2x + 4y = 12 by using slope and y-intercept. Her graph is shown. Which choice supports the graph that she has drawn. A) The slope is positive 1 2 and the y-intercept is (0,3). B) The slope is negative 1 2 and the y-intercept is (0, 3). C) The slope is positive 1 2 and the y-intercept is (0, -3). D) The slope is negative 1 2 and the y-intercept is (0, -3).

Answer 1

Answer:

B) The slope is negative 1/2 and the y-intercept is (0, 3).

Step-by-step explanation:

First we rewrite the equation so we can easily find the slope and y-intercept.  We do this by isolating the y-term:

2x+4y = 12

We want to subtract 2x from each side:

2x+4y-2x = 12-2x

4y = 12-2x

4y = -2x+12

Now we divide both sides by 4 (everything on both sides gets divided!):

4y/4 = -2x/4 + 12/4

y = -2/4x + 3

y = -1/2x + 3

The slope is -1/2 and the y-intercept is 3 (the point (0, 3)).

Her graph shows the y-intercept at (0, 3); this part is correct.

The graph also shows we go down one and over two between points; this is a slope of -1/2, which is correct.

Answer 2

The slope is supposed to be -2 and the y intercept is (0,3)