Question

Can someone help me solve this expression:
15-20×-5+–1=

Answer 1

Hey again :D one sec.

Answer 2

remember PEMDAS

Answer 3

Uh -9-20x, but if you are distributing then -9=20x = -2.222222222

Answer 4

OH WAIT. lol i thought that "x" was a multiply symbol XD

Answer 5

Is this the expression?

\(\Large 15 - 20 \times (-5) + (–1) = \)

Answer 6

Yeah

Answer 7

here is the math :P

15-20x-5+-1
15-5+-1=-9
-9-20x=
+20x to both sides = -9=20x
simple division leads us to -2.222222

Answer 8

Wait no there aren't any parenthesis

Answer 9

You must follow the correct order of operations.
Multiplications and divisions come before additions and subtractions.

Answer 10

simple isolation of the variable right ?

Answer 11

Yeah @Etrainx

Answer 12

\[15 - 20 \times (-5) + (-1)\]
\[15 + 100 + (-1)\]
\[115 + (-1)\]
\[114\]

Answer 13

Should I multiply -20×-5 since its multiplication & following the order of pemdas ?

Answer 14

OH i see

Answer 15

you have 20 * (-5)

Answer 16

i have 20x

Answer 17

But the 20 is negative

Answer 18

The x really means multiplying. You're not working with variables, I believe.

Answer 19

@Halia You're correct. It's -20 because of the minus sign.

Answer 20

when you subtract a negative number it becomes positive though.

Answer 21

Yeah @calculusxy

Answer 22

@Etrainx You need to work with PEMDAS and this states that multiplying is before subtracting. Thus, you need to do -20 times -5.

Answer 23

Wait so I multiped -20×-5 and I got +100

Answer 24

I think these mathletes have it from here :P

Answer 25

Yes that's correct .

Answer 26

That means you must start with \(20 \times (-5)\)

\(\Large 15 - \color{red}{20 \times (-5)} + (–1) =\)

\(\Large = 15 - \color{red}{(-100)} + (–1) \)

Now we only have additions an subtractions, so we do them in the order they appear from left to right:

\(\Large =15 - (-100) + (–1) \)

\(\Large =15 + 100 -1 \)

\(\Large =115 - 1\)

\(\Large =114\)

Answer 27

The work that I did but explained in a better way @mathstudent55

Answer 28

;)

Answer 29

It's confusing, but just remember to take into consideration the sign (plus or minus) because that determines whether the following integer will be negative or positive.

Answer 30

Mkay I understand it now :) thanks guys I really appreciate it !!!

Answer 31

You're very welcome @Halia :)

Answer 32

Order of operations PEMDAS
P - first do what is inside parentheses
E - then do exponents
MD - then do multiplications and divisions from left to right in the order they appear
AS - finally do additions and subtractions in the order they appear from left to right

Answer 33

You're welcome.