Help with 5th grade math?

how do you do this?

9x+2=20

and

-4x=-2

9 Answers

Relevance
  • 1 decade ago
    Favorite Answer

    for 9x + 2 = 20 you're trying to find out what is multiplied by 9 to get a number such that adding 2 to its product will give 20.

    subtract 2 from both sides to get:

    9x = 18

    divide both sides by 9 to get:

    x = 2

    as for -4x = -2:

    divide both sides by -4 to get:

    x = (-2/-4)

    which equals

    1/2. so x = 1/2

  • 1 decade ago

    You want to get the x term on one side of the equals sign and the constant (number) on the other side.

    9x + 2 = 20 Subtract 2 from BOTH sides to keep it in balance

    9x +2 - 2 = 20 - 2 Now isolate the variable (x) by dividing BOTH sides by 9 to keep it in balance:

    9x / 9 = 18 / 9

    x = 2

    See?

    Same with the other one except you have to deal with negative numbers...

    -4x = -2 No constant on the left so you don't have to do any adding or subtracting, just divide BOTH sides by -4 to isolate the variable AND turn it into a positive:

    -4x / 4 = -2 / -4

    x = 2/4 or 1/2

    Easy! :)

  • 1 decade ago

    9x + 2 = 20

    9x + 2 - 2 = 20 - 2

    9x = 18

    9x/9 = 18/9

    x = 2

    -4x = -2

    -4x/-4 = -2/-4

    x = 2/4

    x = 1/2

  • 1 decade ago

    Problem 1:

    9x + 2 = 20

    9x = 20 - 2

    9x = 18

    x = 18/9 or 2

    Problem 2:

    - 4x = - 2

    x = - 2/- 4

    x = 1/2

  • How do you think about the answers? You can sign in to vote the answer.
  • 1 decade ago

    9x + 2 = 20

    Subtract 2 from both sides

    9x = 18

    Divide by 9

    x= 2

    -4x = -2

    Divide by -4, and since - divided by - is +,

    x = 1/2 or 0.5

  • shalu
    Lv 4
    1 decade ago

    9x+2=20

    9x+2 -2 =20 -2

    9x=18

    9x/9=18/9

    x= 2

    -4x=-2

    (-1) -4x= (-1) -2

    4x-2

    4x/4= 2/4

    x= .5

  • 1 decade ago

    9x=18,x=2

    ==================================================

    x=-2/-4=1/2

  • 1 decade ago

    x is obviously 2 making your problem 9*2+2=20 makes sense right? erm... the second one i dont know xD im dumb for a 9th grader always listen in school!!

  • 1 decade ago

    first one is 2

    9(2)+2==20

    second one is .5

    -4(.5)=-2

Still have questions? Get your answers by asking now.