Solving linear equations

Which equation is represented by the algebra blocks in the picture shown?

• • - 4x + 7 = 2x - 5

• 7 + 4x = 2x + 5

• • - 4x + 7 = - 2x + 5

• • - 4x - 7 = 2x + 5

You need to combine like terms when you see more than two like terms on one side of an equation.

Example: 3x + 5 - 2x = 6x + 3

• True

• False

• -2 from both sides of the equal sign

• -5d from both sides of the equal sign

• -2d from both sides of the equal sign

• + 7 on both sides of the equal sign

Is there a mistake on the equation solved? If so where was the mistake made?

• This equation is solved correctly.

• The mistake was made on the first step of collecting the variable on the right side.

• The mistake was made on the second step of collecting the constant on the left side.

Is there a mistake on the equation solved? If so where was the mistake made?

• This equation is solved correctly.

• The mistake was made on the first step of collecting the variable to the right side.

• The mistake was made on the second step of collecting the constant to the left side.

• The mistake was made on the last step when isolating the variable by removing the coefficient.

Is there a mistake on the equation solved? If so where was the mistake made?

• This equation is solved correctly.

• The mistake was made on the first step of expanding the brackets.

• The mistake was made on the second step of collecting the variable to one side.

Find the error in the problem below
19 - 2k = 3k - 1
     +3k   +3k
19 + 1k = -1
-19           -19
k = -20

• They should have divided by 1 for the last step
• They should add 19 instead of subtracting 19
• I can not find an error
• Instead of adding 3k they should subtract 3k

Gary solved the equation as shown in the picture. Which correctly describes the error that Gary made in his work?

• he did not combine 7x and 8x correctly

• he did not divide correctly

• he did not combine -3 and -9 correctly

• he did not make an error in his work