If A = 3x² - 4x + 1, B = 5x² + 3x - 8 and C = 4x² - 7x + 3, then find A + B + C

Solution:

Given, A = 3x² - 4x + 1, B = 5x² + 3x - 8 and C = 4x² - 7x + 3

We have to find A + B + C

A + B = 3x² - 4x + 1 + (5x² + 3x - 8)

= 3x² - 4x + 1 + 5x² + 3x - 8

By combining like terms,

= 3x² + 5x² - 4x + 3x + 1 - 8

By distributive property,

= (3 + 5)x² + (-4 + 3)x + (1 - 8)

= 8x² + (-1)x - 7

A + B = 8x² - x - 7

Now, A + B + C = 8x² - x - 7 + (4x² - 7x + 3)

= 8x² - x - 7 + 4x² - 7x + 3

By combining like terms,

= 8x² + 4x² - x - 7x - 7 + 3

= (8 + 4)x² + (-1 - 7)x + (-7 + 3)

= 12x² + (-8)x + (-4)

= 12x² - 8x - 4

Therefore, A + B + C = 12x² - 8x - 4

✦ Try This: If A = x² + x + 1, B = 4x² - 3x + 2 and C = x² - 4x + 6, then find A + B + C

☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 12

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NCERT Exemplar Class 7 Maths Chapter 10 Problem 68 (iii)

If A = 3x² - 4x + 1, B = 5x² + 3x - 8 and C = 4x² - 7x + 3, then find A + B + C

Summary:

If A = 3x² - 4x + 1, B = 5x² + 3x - 8 and C = 4x² - 7x + 3, then A + B + C is 12x² - 8x - 4

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