1.

Find the product: i. (a + 3) ( a + 5) ii. (3t + 1) (3t + 4) iii. (a – 8) (a + 2) iv. (a – 6) (a – 2)

Answer»

i. (a + 3) (a + 5) 

This is in the form. 

(x + a)(x + b) = x2 + (a + b)x + ab 

Here x = a, a = 3, b = 5 

(a + 3)(a+ 5) = a2 +(a + 5)a + 3.5 

= a2 + 8a + 15 

(ii) (3t + 1)(3t + 4)

This is in the form. (x + a)(x + b) 

= x2 +(a + b)x + ab 

Here x =3t,a = 1, b = 4 

(3t – 1)(3t + 4) = (3t)2+(1+ 4)3t + 1.4 

= 9t2 +5(3t) + 4 = 9t2 +15t + 4 

(iii) (a -8)(a + 2)

This is in the form (x + a)(x + b) = x2 +(a + b)x + ab 

Here x = a, a = -8, b = 2 

(a – 8)(a + 2) = a2 + (-8 + 2)a + (-8)(2) 

= a2 + (-6)a – 16 = a2 – 6a – 16 

(iv) (a – 6)(a – 2)

This is in the form (x + a)(x + b) 

= x2 +(a + b)x + ab 

Here x = a, a = -6,b = -2 

(a – 6)(a – 2) = a2 + (- 6 – 2) a + (-6)(-2) 

=a2 + (- 8)a + 12 

= a2 – 8a + 12


Discussion

No Comment Found

Related InterviewSolutions