# math,correction

posted by on .

can someone correct these for me i'll appreciate it thank.
dirctions: solve

3x-7=2x+8

x = 15

directions: solve
2/5x=-10

x = -25

Directions: solve

-3(x+1)=2(x-8)+3

x= -3.2

1 looks ok.
Show your work on 2 and 3 and we can correct them.

okay this is what i did:
Directions: solve
2/5x = -10

I caught my mistake i think so now i came up with the following:
2/5x =-10
---- ----
2/5 2/5

x = -1

Dirctions: SOLVE
-3(X+1)=2(X-8)+3

my answer: I tried it again but this is what i get now.
-3(x + 1 ) = 2(x -8 )+ 3
-3x - 3 = 2x -16 + 13
-3x -3 = 2x -3
+3 +3
-3x = 2x + 0
-2x -2x

-5x = 0
--- ---
-5 -5

x = 0

Directions: solve
2/5x = -10
Multiply both sides by 5x.
5x*(2/5x)=-10*5x
2=-50x
Divide both sides by 50
2/50 = -50x/50
1/25 = -x
Multiply both sides by -1
-1/25 = x
Check my work.

I caught my mistake i think so now i came up with the following:
2/5x =-10
---- ---- This is the hard way
2/5 2/5
You didn't do this step right.
The left side is 1/x.
The right side is -25.
1/x = -25
and x = -1/25

I think you may not be inverting the denominator and multiplying.

x = -1

Dirctions: SOLVE
-3(X+1)=2(X-8)+3
You should check your answer by putting the value you obtain back into the equation. You know the equation is right if the answer satisfies the equation. Neither x=0 nor x=-1 does that.
First, clear the parentheses.
-3x-3=2x-16+3
subtract 2x from both sides.
-3x-2x-3=2x-2x-16+3
-5x-3=-16+3
Add 3 to both sides.
-5x-3+3=-16+3+3
-5x=-10
Multiply by -1
5x=10
Divide both sides by 5
5x/5=10/5
x=2
Check my work.

my answer: I tried it again but this is what i get now.
-3(x + 1 ) = 2(x -8 )+ 3
-3x - 3 = 2x -16 + 13 +3 not 13
-3x -3 = 2x -3
+3 +3
-3x = 2x + 0
-2x -2x

-5x = 0
--- ---
-5 -5

x = 0

for number one , i thought in order to get x alone i had to divide it to the other side.

can you help me understand please.

let me see if i understood for number one:the answers that they have are the following for the solution options.
A) -4
B) 4
C)25
D)-25

solve for : 2/5x = -10

2/5x = -10 (2/5 is equal to .4)
.4x = -10
after i divide .4 by both sides i get

x = -25

then for number 2:
my options for the answers are:
A)-1
B)1
C)3
D)2
solve: -3(x +1) = 2(x -8 ) +3
-3(x + 1) = 2(x -8) + 3
-3x -3 = 2x - 16 + 3
-3x - 3 = 2x -13
+3 +3
-3x = 2x - 10
-2x -2x

-5x = -10
--- ---
-5 -5

x = 2

Actually I don't know which problem you are talking about but I presume it is the 2/5x = -10
You do need to get x to the other side but it is already in the denominator; therefore, you can't get it to the other side by dividing by x. You divided by 2/5 which will get rid of the 2/5 on the left side but it leaves 1/x. Your expression of
(2/5x)/(2/5)= (2/5x)*(5/2)= 1/x.
On the right side, you have
(-10)/(2/5) = -10*(5/2)= -50/2 = -25
SO, 1/x = -25 and of course then
x = -1/25

OK. See below for what WE have been doing wrong.
let me see if i understood for number one:the answers that they have are the following for the solution options.
A) -4
B) 4
C)25
D)-25

solve for : 2/5x = -10
When you write an equation this way I think you mean 2/(5x) = -10 while you actually mean (2/5)*x=-10. As I interpret the question, x = -1/25 and that accounts for why you thought I messed up and I thought you messed up. As you intended the question,
x = -25.
You really must use parentheses, especially on these boards, so we will know what your question actually is.
The x = 2 is also correct.

2/5x = -10 (2/5 is equal to .4)
.4x = -10
after i divide .4 by both sides i get

x = -25

sorry now i know. i didn't know

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