randRange( 2, 10 ) randRangeNonZero( -10, 10 ) randRange( 2, 10 ) randRangeNonZero( 2, 10 ) fractionReduce( D - B, A - C ) randRange(1,3)

[Click to learn about the “ What? Why? How?" strategy]

To use this strategy, ask yourself these “ What? Why? How?" questions after each hint in a problem.
What does this step mean to you?
Why is it helpful to take this step?
How do you know this step is right?
As a reminder to ask yourself these questions, they will sometimes appear in purple.

What if I can’t do it?
Many students are not sure what to say, or think their answer isn’t good. That is fine, as long as you try to think about the question, by typing or saying the answer to yourself.

Solve for x:

Ax + B = Cx + D
x =
[ $("#guessans").val(), $("#firsttext").val(), $("#secondtext").val(), $("#thirdtext").val(), $("#fourthtext").val() ]
var correct = ( D - B ) / ( A - C ); var solutionDiv = $("<div>").text(correct); var validator = Khan.answerTypes.number.createValidator(solutionDiv); return validator(guess[0]);
if (guess != null) { $("#guessans").val(guess[0]); } else { $("#guessans").val(""); }
if (guess != null) { $("#firsttext").val(guess[1]); $("#secondtext").val(guess[2]); $("#thirdtext").val(guess[3]); $("#fourthtext").val(guess[4]); } else { $("#firsttext").val(""); $("#secondtext").val(""); $("#thirdtext").val(""); $("#fourthtext").val(""); }
an integer, like 6
a simplified proper fraction, like 3/5
a simplified improper fraction, like 7/4
a mixed number, like 1\ 3/4
an exact decimal, like 0.75

Subtract Cx from both sides:

(Ax + B) - Cx = (Cx + D) - Cx

A - Cx + B = D

What does this step mean to you?
Why is it helpful to take this step?
How do you know this step is right?

B > 0 ? "Subtract" : "Add" abs(B) B > 0 ? "from" : "to" both sides:

(A - Cx + B) + -B = D + -B

A - Cx = D - B

Divide both sides by A - C.

\frac{A - Cx}{A - C} = \frac{D - B}{A - C}

What does this step mean to you?
Why is it helpful to take this step?
How do you know this step is right?

Simplify.

x = SOLUTION

Subtract Ax from both sides:

(Ax + B) - Ax = (Cx + D) - Ax

B = C - Ax + D

What does this step mean to you?
Why is it helpful to take this step?
How do you know this step is right?

D > 0 ? "Subtract" : "Add" abs(D) D > 0 ? "from" : "to" both sides:

B + -D = (C - Ax + D) + -D

B - D = C - Ax

Divide both sides by C - A.

\dfrac{B - D}{C - A} = \dfrac{C - Ax}{C - A}

What does this step mean to you?
Why is it helpful to take this step?
How do you know this step is right?

Simplify.

SOLUTION = x