Algebra 1 : How to use the grid method for FOIL

Study concepts, example questions & explanations for Algebra 1

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1

Example Question #1 : How To Use The Grid Method For Foil

Possible Answers:

Correct answer:

Explanation:

           

      

     

 

 

Example Question #1 : How To Use The Grid Method For Foil

Multiply:

Possible Answers:

Correct answer:

Explanation:

To multiply two binomials, both terms in the first binomial need to be multiplied with both terms in the second binomial. A good way to make sure that all of the pairs are multiplied is to set up the box/grid:

Box2b

In each empty box, multiply the intersecting terms:

Box2a

Now, combine like terms. 3x and 8x are both terms with x, so we can add them to be 11x.

Final answer [in descending order of powers of x:

Example Question #2 : How To Use The Grid Method For Foil

Multiply:

Possible Answers:

Correct answer:

Explanation:

To multiply two binomials, both terms in the first binomial need to be multiplied with both terms in the second binomial. A good way to make sure that all of the pairs are multiplied is to set up the box/grid:

Box1a

In each empty box, multiply the intersecting terms: 

 

Box1b

Now, combine like terms. -6x and 4x are both terms with x, so we can add them to be -2x.

Final answer:

Example Question #3 : How To Use The Grid Method For Foil

Use the grid method to distribute and simply .

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 1a

Top left corner:

 

Top right corner:

Bottom left corner:

Bottom right corner:

Add along the diagonal:

Combining our terms:

Example Question #4 : How To Use The Grid Method For Foil

Expand  using the grid method.

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 2

 

Top left corner:

 

Top right corner:

Bottom left corner:

Bottom right corner:

Add along the pink diagonal:

Combining our terms:

Example Question #5 : How To Use The Grid Method For Foil

Expand  using the grid method.

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 3

 

Top left corner:

 

Top right corner:

Middle left:

Middle right:

Bottom left corner:

Bottom right corner:

Add along the first (pink) diagonal:

Add along the second (blue) diagonal:

Combining our terms:

Example Question #6 : How To Use The Grid Method For Foil

Expand  using the grid method.

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 4

 

Top left corner:

 

Top right corner:

Bottom left corner:

Bottom right corner:

Add along the (pink) diagonal:

Combining our terms:

Example Question #7 : How To Use The Grid Method For Foil

Expand  using the grid method.

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 5

 

Top left corner:

 

Top right corner:

Bottom left corner:

Bottom right corner:

Add along the (pink) diagonal:

Combining our terms:

Example Question #8 : How To Use The Grid Method For Foil

Expand  and  using the grid method. Compare your answers.

Possible Answers:

The answers are the same except that the middle terms are different.

The answers are completely different.

The answers have opposite signs.

The answers are the same.

Correct answer:

The answers are the same.

Explanation:

Let's look at the grid for  first.

Alg 1 prob 6a

 

Now let's look at the grid for .

Alg 1 prob 6b

 

Top left corner:

  or 

Both grids give us .

Top right corner:

 or 

Bottom left corner:

 or 

Bottom right corner:

 or 

Both grids give us  here.

Add along the (pink) diagonals in each grid:

 or 

Both grids give us .

Combining our terms in either grid, we get:

So the answers are exactly the same!

Example Question #9 : How To Use The Grid Method For Foil

Expand  using the grid method.

Possible Answers:

Correct answer:

Explanation:

Alg 1 prob 7

 

Top left corner:

 

Top right corner:

Bottom left corner:

 

Bottom right corner:

 

Add along the (pink) diagonal:

Combining our terms, we get:

← Previous 1
Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: