Simplify the expression 3x + 9x, and choose the best choice:

Simplify the expression 8x + 6x = 28, and choose the best choice:

Some equations need to be simplified by adding x’s (instead of numbers).

A number multiplied by an x is called a “coefficient.”

To add (combine) x’s, you just add their coefficients.

To subtract x’s, you subtract their coefficients.

Another way to subtract x’s is to change the subtraction to addition of the opposite first.

Simplify each expression below. Select the best possible choice.

13x - 5x

Simplify each expression below. Select the best possible choice.

-6x - 4x

Simplify each expression below. Select the best possible choice.

x + 6x

Simplify each expression below. Select the best possible choice.

13x - x

You can change a single x to 1x in order to use the adding coefficients shortcut.

You can change a -x to -1x in order to use the adding coefficients shortcut.

Alex can read 36 pages per hour and Jaci can read 44 pages per hour. How many hours will it take them to read 240 pages?

Choose the equation that best represents this problem.

Brittney can bake 7 cakes per hour and Ed can bake 5 cakes per hour. How many hours will it take them to bake 48 cakes?

Choose the equation that best represents this problem.

Work problems usually translate into an equation with more than one x.

In a work problem, the rate multiplied by the time equals the total amount of work a person does.

Driver #1 and driver #2 are headed straight toward each other. Driver #1 is driving at 65 mph, and driver #2 is driving at 55 mph. If the two drivers are 360 miles apart, how many hours will it be before they meet?

True or False: This is the correct equation to help us solve this problem: 65x+55x=360

Plane #1 and plane #2 are headed straight toward each other. Plane #1 is flying at 500 mph and plane #2 is flying at 575 mph. If the two planes are 5,375 miles apart, how many hours will it be before they meet?

True or False: This is the correct equation to help us solve this problem: 500x+575x=5,375

Runner #1 and runner #2 are headed straight toward each other. Runner #1 is traveling at 7 mph, and runner #2 is traveling at 10 mph. If the two runners are 34 miles apart, how many hours will it be before they meet?

Which equation will solve this problem?

Solve: Bird #1 and bird #2 are headed straight toward each other. Bird #1 is flying at 36 mph, and bird #2 is flying at 14 mph. If the two birds are 400 miles apart, how many hours will it be before they meet?