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Which starts higher: y = 3x - 1 or x 0, 1, 2; y 2, 3, 4

Step by step, with the reason for every step · Compare two functions · Algebra 1

Step by step

The question

Question: which starts higher: function A, y = 3x − 1, or function B, x: 0, 1, 2; y: 2, 3, 4?

A: y = 3x − 1
= B: x: 0, 1, 2; y: 2, 3, 4

The start value is y when x is 0.

The bigger one starts higher.

starts higher = bigger start value

1 Start value of A

In y = m x plus b, b is the number added: −1.

= y = 3x − 1: b = −1

2 Start value of B

In the table, at x = 0, y is 2.

= x = 0: y = 2

3 Compare

2 is bigger.

So function B starts higher.

= −1 < 2 → B starts higher

Careful!

Function A grows faster.

But it starts lower.

Careful: the faster one is not the higher start

4 Check

Let's check: both lines on one grid.

Line B crosses the y-axis higher.

So the answer is right!

Let's look back.

First: start value of A.

Then: start value of B.

Then: compare.

Last: check.

Answer
Careful: the faster one is not the higher start

Your turn

Try this one yourself, then check:

Which starts higher: function A, A: y = 5x
Show the answer
B starts higher

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