(4pq+3q)2 − (4pq−3q)2= ____________.
48pq2
48p2q
44p2q
44pq2
(4pq+3q)2−(4pq−3q)2 We have: (a+b)2=a2+2ab+b2(a−b)2=a2−2ab+b2 So, (4pq+3q)2−(4pq−3q)2 =[(4pq)2+(3q)2+2(4pq)(3q)]−[(4pq)2+(3q)2−2(4pq)(3q)] =24pq2+24pq2 =48pq2
Show that
(i) (3x + 7)2 − 84x = (3x − 7)2 (ii) (9p − 5q)2 + 180pq = (9p + 5q)2
(iii)
(iv) (4pq + 3q)2 − (4pq − 3q)2 = 48pq2
(v) (a − b) (a + b) + (b − c) (b + c) + (c − a) (c + a) = 0