Steply

Graph y > 1/2x - 1 and y < -x + 3

Step by step, with the reason for every step · Systems of inequalities · Algebra 1

Step by step

The question

Question: graph y > (1/2)x − 1 and y < −x + 3.

① y > 12x − 1 and ② y < −x + 3

We shade the answer of each one.

Where both are shaded, both are true.

answer = the part shaded twice

1 Graph ①

Draw the grid.

①: The sign is more than, with no "or equal to".

So the line is dashed.

① > → dashed line

b = −1.

Start on the y-axis at −1.

m = 1/2.

Go right 2,

then up 1.

Dot.

Join the dots: dashed.

Which side?

We test one point: (0, 0).

Put x = 0 and y = 0 into ①.

① 0 > 12(0) − 1
0 > −1 true

Is 0 more than −1?

Yes, true.

So we shade the side with (0, 0), in red.

2 Graph ②

②: The sign is less than, with no "or equal to".

So the line is dashed.

② < → dashed line

b = 3.

Start on the y-axis at 3.

m = −1.

Go right 1,

then down 1.

Dot.

Join the dots: dashed.

Which side?

We test one point: (0, 0).

Put x = 0 and y = 0 into ②.

② 0 < −(0) + 3
0 < 3 true

Is 0 less than 3?

Yes, true.

So we shade the side with (0, 0), in blue.

3 Where both are shaded

This part is shaded twice.

It is the answer.

Careful!

The answer is not everything we shaded.

Only the part shaded twice works in both.

Careful: not every shaded part ✗

4 Check

Let's check with a point in the purple part: (−1, 1).

Put it into ①.

① 1 > 12(−1) − 1
1 > −32 true

Now ②.

② 1 < −(−1) + 3
1 < 4 true

True in both!

So the answer is right.

Let's look back.

First: graph ①.

Then: graph ②.

Then: where both are shaded.

Last: check.

Answer
0 < 3 true

Your turn

Try this one yourself, then check:

y > 12x − 4 and y < −x + 2
Show the answer
the part shaded twice

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