Question 31 of 43intermediate🔧 ApplyShort Answer8 marks
Use suitable identities to find the following products:
(i)
(-3x + 4)^2
Answer
- 24x + 16
(ii)
(2s + 7)(2s - 7)
Answer
- 49
(iii)
( + 1/2)( - 1/2)
Answer
- 1/4
(iv)
(2n + 7)(2n - 7)
Answer
- 49
(v)
(s - 2t)( + 2st + )
Answer
-
(vi)
(1/2r - 4r)^2
Answer
49/4
(vii)
(-3m + 4k - l)^2
Answer
+ + - 24mk - 8kl + 6lm
(viii)
(x - 1/3 y)^3
Answer
- y + 1/3 x - 1/27
Explanation
We use standard algebraic identities to find the products without direct multiplication. For (i) and (vi), we use the identity (a - b)^2 = - 2ab + or (a + b)^2 = + 2ab + . For (ii), (iii), and (iv), we use the difference of squares identity (a + b)(a - b) = - . For (v), we use the identity (x - y)( + xy + ) = - . For (vii), we use (a + b + c)^2 = + + + 2ab + 2bc + 2ca. For (viii), we use (a - b)^3 = - + - .