Solve for the dimensions of the area model below and then write an equation showing how the area as a sum is equivalent to the area as a product.

Full question:

For each multiplication expression, sketch an area model. Label the dimensions and the area of each part. Then write an equation showing that the area as a product equals the area as a sum. a. (x+1)(x+2), b. 3(2x+5), c. (2x-3)(x+2), d. (x-1)(y-1), e. -2y(y+3), f. (-x+1)(3x+y-4)

Answer and explanation:

a. (x+1)(x+2)= x×x+x×2+1×x+1×2

The dimensions (length and width) is x+1 and x+2

b. 3(2x+5) = 3×2x+3×5

The dimensions is 3 and 2x+5

c. (2x-3)(x+2)= 2x×x+2x×2-3×x-3×+2

The dimensions are 2x-3 and x+2

d. (x-1)(y-1)= x×y+x×-1-1×y-1×-1

Dimensions are x-1 and y-1

e. -2y(y+3)= -2y×y-2y×3

Dimensions are -2y and y+3

f. (-x+1)(3x+y-4)= -x×3x-x×y-x×-4+1×3x+1×y+1×-4

Dimensions are -x+1 and 3x+y-4

step-by-step explanation:

equation

you are asked to write the equation

  expression = 0

using the given expression. when you do that, you have

  2x^2-2x-12 = 0

factoring

you can see that each of the coefficients is even, so a factor of 2 can be removed immediately.

  2(x^2 -x -6) = 0

if you multiply the binomials (x+a)(x+b), you get

  (x +a)(x +b) = x^2 +(a+b)x +ab

this tells you the coefficient of x is the sum of two factors of the constant term. here, that means -1 is the sum of two factors of -6. we want to know those factors so we can factor the trinomial.

  -6 = -1×6 = -2×3 = -3×2 = -6×1

the factor pair that sums to -1 is {-3, 2}, so our factorization is

  2(x -3)(x +2) = 0

solutions

the solutions to this equation are the values of x that make the product zero. a product is zero only when only of the factors of the product is zero. here, that means

  x - 3 = 0

  x = 3 . . . add 3 to both sides of the equation

or

  x +2 = 0

  x = -2 . . . add -2 to both sides of the equation

the solutions to the equation are x=3 or x=-2. both of these values of x satisfy the equation—they make it be true.