Math help please?

Question

Hi i need some math help, im in grade 9 and have a unit test on this stuff soon, algebra/polynomials. i was just wondering for the question

13=5-8m would the final answer be 21 over 5 (fraction) or would i have to divide 21 by 5 and it would be 4.2?

also if you can can you please post some questions about polynomails and anything in the first unit of grade 9. thanks

Answer 1

m= -1

You can do this one in your head. 5 + what = 13. 8 of course. But your problem says -8m instead of what. So 8 must = -8m. We need to do something to -8 to make it positive 8. We have to multiply it by -1. Multiplying two negatives makes a positve. So m must equal -1 that way -8 times -1 will equal 8.

Answer 2

It doesn't matter if its decimal or fraction. It could be 21/5 and 4.2

Here's a couple of examples
Simplify 10x3 – 14x2 + 3x – 4x3 + 4x – 6

10x3 – 14x2 + 3x – 4x3 + 4x – 6
= (10x3 – 4x3) + (–14x2) + (3x + 4x) – 6
= 6x3 – 14x2 + 7x – 6
Simplify 25 – (x + 3 – x2)

The first thing I need to do is take the negative through the parentheses:

25 – (x + 3 – x2)
= 25 – x – 3 + x2
= x2 – x + 25 – 3
= x2 – x + 22

If it helps you to keep track of the negative sign, put the understood 1 in front of the parentheses:

25 – (x + 3 – x2)
= 25 – 1(x + 3 – x2)
= 25 – 1x – 3 + 1x2
= 1x2 – 1x + 25 – 3
= 1x2 – 1x + 22
= x2 – 1x + 22

While the first format (without the 1's being written in) is the more "standard" format, either format should be acceptable (check with your instructor). You should use the format that works most successfully for you.
Simplify x + 2(x – [3x – 8] + 3)

This is the kind of problem that us math teachers love to put on tests (yes, we're cruel people), so you should expect to need to be able to do this. This is just an order of operations problem with a variable in it. Work carefully from the inside out, and you should be fine:

x + 2(x – [3x – 8] + 3)
= x + 2(x – 1[3x – 8] + 3)
= x + 2(x – 3x + 8 + 3)
= x + 2(–2x + 11)
= x – 4x + 22
= –3x + 22
Simplify [(6x – 8) – 2x] – [(12x – 7) – (4x – 5)]

Work from the inside out:

[(6x – 8) – 2x] – [(12x – 7) – (4x – 5)]
= [6x – 8 – 2x] – [12x – 7 – 4x + 5]
= [4x – 8] – [8x – 2]
= 4x – 8 – 8x + 2
= –4x – 6
Simplify –4y – [3x + (3y – 2x + {2y – 7} ) – 4x + 5]

–4y – [3x + (3y – 2x + {2y – 7} ) - 4x + 5]
= –4y – [3x + (3y – 2x + 2y – 7) - 4x + 5]
= –4y – [3x + (–2x + 5y – 7) – 4x + 5]
= –4y – [3x – 2x + 5y – 7 – 4x + 5]
= –4y – [3x – 2x – 4x + 5y – 7 + 5]
= –4y – [–3x + 5y – 2]
= –4y + 3x – 5y + 2
= 3x – 4y – 5y + 2
= 3x – 9y + 2

Answer 3

I'm not sure if you typed the problem correctly. . .

If it's 13 = 5 -8m, then you need to isolate the variable in the problem.

1) Subtract 5 from both sides --> 8 = -8m

2) Divide both sides by -8 ----> -1 = m

Answer: m = -1

Answer 4

First look at the equation.
What does 5+8 equal?? 13??
So m = -1

Answer 5

ok first were did u get 21 from the problem is 13=5-8m or
-8m+5=13 contact me at [e-mail]

Answer 6

Here is my answer
13=5-8m
subtract 5 from both sides
13-5=5-5-8m
8=-8m
Divide both sides by-8
8/-8=-8m/-8
-1=m

Check ans.
13=5-(8*-1)
13=5-(-8)
13=13
I hope this helps

Answer 7

all u do is subtract 5 from each side then u have 8= -8m therefore m=-1

Answer 8

88
+5dsfsdfd15sd4f53 46ds5f 4ds6
f5sd14 sd53fds

Answer 9

the answer to that problem would be m= -1