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Which expression is equivalent to (x^2)(x^6)?

Question 4 of module 1 · Step by step, with the reason for every step · SAT Practice Test 1 · SAT Math

Step by step

The question

Question: which expression is equivalent to (x²)(x⁶)?

Equivalent means: the same value for every x.

Brackets next to each other mean times.

(x2)(x6)

There are four choices.

First we simplify it, the normal way.

Then we pick.

1 Add the powers

The rule: when we multiply the same letter, we add the powers.

xa xb = xa + b

We add the powers of x.

= x2 + 6

2 plus 6 is 8.

So we get x⁸.

= x8

2 Pick the choice

Our answer is x⁸.

That is choice A.

A) x8

3 Why not the others

B is 2x⁸.

Wrong: x × x is x², not 2x.

B) 2x8 ✗ x × x is x², not 2x

C is x¹².

Wrong: 2 × 6: multiplied the powers; we add them.

C) x12 ✗ 2 × 6: multiplied the powers; we add them

D is 2x¹².

Wrong: multiplied the powers and doubled.

D) 2x12 ✗ multiplied the powers and doubled

Let's look back.

First: add the powers.

Then: pick the choice.

Last: why not the others.

Answer
= x8

Your turn

Try this one yourself, then check your answer:

Simplify (x5)(x6)
Show the answer
x11

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