Julie says that

**3**

*a*² + 2*a*+ 5*a*² = 10*a*³and

**7**

*b*x 5*b*² x 6 = 210*b*Do you agree with Julie? If not, what are the mistakes in her algebraic manipulations?

Enter your responses under

*Comments*.

Note: to enter superscripts, you may use the code

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I do not agree with Julie.

ReplyDeleteIt should be :

3a² + 2a + 5a²

= (3a² + 5a²) + 2a

= 8a² + 2a(Ans.)

3a² and 5a² cannot be added with 2a as they are of different "power".

It should be:

7b x 5b² x 6

= (7b x 5b²) x 6

= 35b³ x 6

= 210b³(Ans.)

b x b² = b³

Julie probably took b² ÷ b = b. Therefore, her final answer is 210b without the "power" of 3.

JJ(:

I don't agree with her.

ReplyDelete1) 3a² and 5a² cannot be added together with 2a. That is because they have different "power", like 2a and 2a².

It should be: 3a² + 2a + 5a²

= (3a² + 5a²) + 2a

= 8a² + 2a

2) Julie took the amount with the "power" like a fraction, so it became b² ÷ b, which lead her to the answer, 210b, without the "power of 3" behind.

It should be: 7b x 5b²

= 35b³

35b³ x 6

= 210b³

This comment has been removed by the author.

ReplyDelete1) 3a² + 2a + 5a²

ReplyDelete=(3 x a x a) + (2 x a) + (5 x a x a)

=(8 x a x a) + (2 x a)

=8a² + 2a

2) 7b x 5b² x 6

=(7 x b) x (5 x b x b) x 6

=(7 x 5) x (b x b x b) x 6

=35b³ x 6

=210b³

Both numbers have different powers. There are like 8 groups of a² and 2 groups of a. But the a and a² are different powers so they cannot be grouped together. Therefore Julie's first answer is wrong.

As for her second answer, which is also incorrect, she probably "grouped" the "b"s together and treated them as one variable, so her answer was not to the power of 3.

This comment has been removed by the author.

ReplyDeleteI do not agree with Julie.

ReplyDeleteFor number one, the workings are suppose to be

= 3a² + 2a + 5a²

= (3a² + 5a²) + 2a <------- Only equivalent units can be added together.

= (8a² + 2a)<-------------Answer

So basically, julie just added all the "powers" and the digits together to form a irregular expression.

For question two,

The answer should be

=7b x 5b² x 6

= (7b x 5b²)x 6<------Bracketed to make the expression clearer

= 35b³ x 6<-------- Note that b x b² = b³

= 210b³<----------Answer

Basically what julie did is that she made all the "b" into one variable so the b³ will be grouped into a single "b" thus leading to her mistakes in her calculations

I do not agree with Julie.

ReplyDeleteFor the first question, it should be 3a²+2a+5a²=8a²+2a.

Julie added the numbers, 3,2 and 5, together and supposed that a²+a=a³.

For the second question, it should be 7bx5b²x6=210b³. Julie only multiplied the numbers and only used b without using b². So she supposed that 7bx5b²x6=210b.

I do not agree with Julie.

ReplyDeleteQuestion 1 should be:

3a²+2a+5a²=(3a²+5a²)+2a

=8a²+2a

Julie most probably added 2a to 8a². They cannot be added together as they are of different values.

Question 2 should be:

7bx5b²x6=35b³x6

=210b³

Julie most likely thought that b² was the same as b and grouped them under the same value.

I do not agree with Julie

ReplyDelete1a) 3a² + 2a + 5a² = 10a³

3a² +2a + 5a²

=(3a² +5a² )+ 2a

=(8a² + 2a)

2a)7b x 5b² x 6 = 210b

=35b7² x6

=210³

This comment has been removed by the author.

ReplyDeleteThis comment has been removed by the author.

ReplyDeleteI do not agree with Julie.

ReplyDeleteFor question 1, 3a^2+2a+5a^2 cannot be added as they are of different values. It should be (3a^2+5a^2)+2a, which will give us 8a^2+2a.

For question 2, 7bx5b^2x6 should equal to 35b^3x6, which gives us 210b^3

I do not agree with Julie.

ReplyDeleteQuestion 1:

3a²+ 2a+ 5a²=(3a²+5a²) +2a

= 8a²+ 2a

Julie might have added 2a to 8a². They can't be added together as they are of different values.

Question 2:

7bx5b²x 6=35b³x6

= 210b³

Julie might have thought that b² was the same as b and grouped them under the same value.

I do not agree Julie.

ReplyDeleteQuestion 1

3a² + 2a + 5a² = 3a x a + 2a + 5a x a

= 8a²+2a

7b x 5b² x 6 = 7b x 5b x b x 6

= (7 x 5 x 6 )( b x b x b)

= 210b³

I do not agree with Julie.

ReplyDeleteIt should be:

3a² + 2a + 5a² = 8a² + 2a

7b x 5b² x 6 = 210b³