Question 85 (x)
Expand the following, using suitable identities.
(2x−5y)(2x−5y)
We have, (2x−5y)(2x−5y)=(2x−5y)2=(4x)2+(5y)2−2×2x×5y [using the identity, (a−b)2=a2+b2−2ab]=16x2+25y2−20xy
Question 85 (vii)
(2x+9)(2x−7)
Expand the following, using suitable identities: (−2x+5y−3z)2.
Expand the following, using suitable identities: 1)(−2x+3y+2z)2 2)(−2x+5y−3z)2. [4 MARKS]