Question

Forming quadratic expression.Two consecutive odd numbers are such that their product is 35.find the numbers​

Answer 1

Answer:

 Numbers are 5 , 7

Step-by-step explanation:

Forming quadratic equation and solving:

  Let the two consecutive odd numbers be (2x + 1) and (2x + 3)

         Their product = 35

(2x + 1)(2x + 3) = 35

Use FOIL method.

       2x*2x + 2x*3  + 1*2x + 1*3 = 35

              4x² + 6x  + 2x + 3       = 35

      Combine like terms

                            4x² + 8x  + 3    = 35

                         4x² + 8x + 3 - 35 = 0

                            4x² + 8x  - 32   = 0

Quadratic equation: 4x² + 8x - 32 = 0

 Solving:

                 4x² + 8x - 32 = 0

Divide the entire equation by 2

                $\sf \dfrac{4}{2}x^2 +\dfrac{8}{2}x - \dfrac{32}{2}=0$

                  2x² + 4x - 16 = 0

Sum = 4

Product = -32

Factors = 8 , (-4)

When we multiply 8*(-4) = -32 and when we add 8 + (-4) = 4.

Rewrite the middle term

2x² + 8x - 4x  - 16 = 0

 2x(x + 4) - 4(x + 4) = 0

   (x + 4) (2x - 4) = 0

2x - 4 = 0   {Ignore x +4 = 0  as it gives negative number}

2x = 4

   x = 4/2

   x= 2

2x + 1 = 2*2 + 1 = 5

2x + 3 = 2*2 +3 = 7

   The numbers are 5 , 7