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! :)
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
