Question

ayudaaaa por favor ​

Answer 1

Explicación paso a paso:

1)

$A + B \\ (3 {x}^{3} + 4x {}^{2} + 7x - 12) + (9 {x}^{4} - 4x {}^{2} + 8x + 12) \\ 9 {x}^{4} + 3x {}^{3} + 15x$

b)

$B - C \\ (9 {x}^{4} - 4 {x}^{2} + 8x + 12) - (7x {}^{3} - 7 {x}^{2} + 5x) \\ 9 {x}^{4} - 4x {}^{2} + 8x + 12 - 7x {}^{3} + 7 {x}^{2} + 5x \\ 9 {x}^{4} - 7 {x}^{3} + 3x {}^{2} + 13x + 12$

c)

$C + B \\ (7x {}^{3} - 7 {x}^{2} + 5x) + (9 {x}^{4} - 4 {x}^{2} + 8x + 12) \\ 9 {x}^{4} + 7x {}^{3} - 11x {}^{2} + 13x + 12$

d)

$C - B \\ (7 {x}^{3} - 7 {x}^{2} + 5x) - (9x {}^{4} - 4 {x}^{2} + 8x + 12) \\ 7 {x}^{3} - 7 {x}^{2} + 5x - 9 {x}^{4} + 4 {x}^{2} - 8x - 12 \\ - 9x {}^{4} + 7 {x}^{3} - 3 {x}^{2} - 3x - 12$

e)

$C +A \\ (7 {x}^{ 3} - 7 {x}^{2} + 5x) + (3 {x}^{3} + 4 {x}^{2} + 7x - 12) \\ 10 {x}^{3} - 3 {x}^{2} + 12x - 12$

f)

$A - B \\ (3 {x}^{3} + 4 {x}^{2} + 7x - 12) - (9x {}^{4} - 4 {x}^{2} + 8x + 12) \\ 3 {x}^{3} + 4 {x}^{2} + 8x + 12 - 9x {}^{4} + 4 {x}^{2} - 8x - 12 \\ - 9 {x}^{4} + 3x {}^{3} + 8x {}^{2}$

g)

$B - A \\( 9 {x}^{4} - 4 {x}^{2} + 8x + 12) - (3 {x}^{3} + 4x {}^{2} + 7x - 12) \\ 9 {x}^{4} - 4x {}^{2} + 8x + 12 - 3x {}^{3} - 4 {x}^{2} - 7x + 12 \\ 9 {x}^{4} - 3x {}^{3} - 8 {x}^{2} + x + 24$

h)

$A - C \\ (3 {x}^{3} + 4x {}^{2} + 7x - 12) - (7x {}^{3} - 7 {x}^{2} + 5x) \\ 3x {}^{3} + 4 {x}^{2} + 7x - 12 - 7x {}^{3} + 7 {x}^{2} - 5x) \\ - 4x { }^{3} + 11x {}^{2} + 2x - 12$

i)

$A + B + C \\ (3 {x}^{3} + 4 {x}^{2} + 7x - 12) + (9x {}^{4} - 4 {x}^{2} + 8x + 12) + (7 {x}^{3} - 7 {x}^{2} + 5x) \\ 9 {x}^{4} + 10 {x}^{3} - 7 {x}^{2} + 20x$

j)

$(B + C) - A \\( (9x {}^{4} - 4x {}^{2} + 8x + 12) + (7 {x}^{3} - 7x {}^{2} + 5x)) - (3 {x}^{3} + 4 {x}^{2} + 8x + 12) \\ (9 {x}^{4} + 7x {}^{3} - 11x {}^{2} + 13x + 12) -3x {}^{3} - 4 {x}^{2} - 8x - 12 \\ 9 {x}^{4} + 4 {x}^{3} - 15 {x}^{2} + 5x$

espero que sea de tu ayuda

Saludos :)