We Distribute, Yet Things Multiply Class 8 Long Question Answer
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We Distribute, Yet Things Multiply Class 8 Long Question Answer
We Distribute, Yet Things Multiply Class 8 Long Question Answer
Question 1.
Simplify:
(x + y)(z - p) + (x- y) (z + p) + 2 (xz + yp).
Solution:
Given expression
= (z - p) + y (z - p) + x(z + p) - y (z + p) + 2xz + 2yp
= xz - xp + yz - yp + xz + xp - yz - yp + 2xz + 2yp
= (1 + 1 + 2)xz + (1 - 1)xp + (1 - 1 )yz + (-1 - 1 + 2 )yp
= 4xz + 0 × xp + 0 × yz + 0 × yp = 4xz.
Question 2.
Show that
(9x - 5y)² + 180xy = (9x + 5y)².
Solution:
L.H.S. = (9x - 5y)² + 180xy
= 81x² - 2 × 9x × 5y + 25y² + 180xy
= 81x² - 90xy + 25y² + 180xy
= 81x² + 90xy + 25y²
= (9x)² + 2 × 9x × 5y + (5y)²
= (9x + 5y)² = R.H.S.