Question

Find the products using suitable identity:

Answer 1

Answer:

Step-by-step explanation:

a) Identity : (a- b)² = a²- 2ab +  b²

(t - 2)(t -2) = (t-2)²            {a = t & b =2}

                 = t² -2*t*2 + 2²

                 = t² - 4t + 4

b) (a + b)(a - b) = a² - b²

a = 3y   & y = 2z

(3y - 2z) (3y +2z)  = (3y)² - (2z)²

                             = 3²y² - 2²z²

                              = 9y² - 4z²

c) (x + a)(x + b) =x² + (a+b)x + ab

105 * 98 = (100 + 5) (100 - 2)  {here, x = 100 ; a = 5 ; b = -2}

              = 100² + (5 +(-2) ) *100 + (5)*(-2)

              = 10000 + (3)*100 - 10

              = 10000 + 300 - 10

              = 10290

Answer 2

Hello!

a) (t - 2)(t - 2) = (t - 2)² = t² - 4t + 4

b) (3y - 2z)(3y + 2z) = (3y)² - (2z)² = 9y² - 4z²

c) 105 × 98 = 10290

Good luck! :)