Question

(-2a + 5b - 3c)^2 expand ​

Answer 1

Step-by-step explanation:

-2×a^2 + 5×b^2 - 3×c^2

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Answer 2

We have been asked to expand (-2a + 5b - 3c)² . For that we simply need to follow the given steps :

1. Find which identity can be applied.
2. Write the expansion of the identity.
3. Put up the values
4. Simplify

Solution :

Identity :

(-2a + 5b - 3c)² is in the form of (a + b + c)² . As (a) and (c) are in negative forms ; we will consider them as :

→ ((-a) + b + (-c))² .

The expansion of the identity :

→ (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca

Putting up the values :

→ (-a) = -2a

→ b = 5b

→ (-c) = -3c

So :

→ (-2 + 5b + (-3c)) = (-2a)² + 5b² + (-3c)² + 2 × -2a × 5b + 2 × 5b × -3c + 2 × -3c × -2a .

→(-2 + 5b + (-3c)) = 4a² + 25b² - 9c² + 2 × -10ab + 2 × -15bc + 2 × 6ca .

Note : In the above step : Negative value of (-2) changed as -2 × -2 = 4 ; thus cancelling the negative sign .

→ (-2 + 5b + (-3c))² = 4a² + 25b² - 9c² - 20ab - 30bc + 12ca .

Hence Expanded.