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| 1. |
Expand each of the following using suitable identities (-2x+5y-3z)² |
| Answer» We know that(a+b+c)² = a² + b² + c² + 2(ab + bc + ca)So,(-2x + 5y - 3z)²= (-2x)² + (5y)² + (-3z)² + 2 [ (-2x)*5y + 5y*(-3z) + (-3z)*(-2x) ]= 4x² + 25y² + 9z² + 2 [ (-10xy) + (-15yz) + 6xz ]= 4x² + 25y² + 9z² - 20xy - 30yz + 12xz | |