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Which starts higher: y = 2x + 5 or x 0, 1, 2; y 3, 7, 11

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 = 2x + 5, or function B, x: 0, 1, 2; y: 3, 7, 11?

A: y = 2x + 5
= B: x: 0, 1, 2; y: 3, 7, 11

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: 5.

= y = 2x + 5: b = 5

2 Start value of B

In the table, at x = 0, y is 3.

= x = 0: y = 3

3 Compare

5 is bigger.

So function A starts higher.

= 5 > 3 → A starts higher

Careful!

Function B 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 A 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 = x + 8
Show the answer
A starts higher

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