Question

Calcule o valor numérico das expressões algébricas é pra hoje pfvvv
(Responder as 03 questões)
Obrigada.

Answer 1

Oie, Td Bom?!

I.

a)

$= - 5a - 8b - c {}^{2}$

$= - 5 \: . \: ( - 3) - 8 \: . \: 4 - ( - 9) {}^{2}$

$= 15 - 32 - 81$

$= 15 - 113$

$= - 98$

b)

$= - x {}^{2} - y {}^{2} - xy + 18$

$= - ( - 2) {}^{2} - ( - 10) {}^{2} - ( - 2) \: . \: ( - 10) + 18$

$= - 4 - 100 + 2 \: . \: ( - 10) + 18$

$= - 4 - 100 - 20 + 18$

$= - 124 + 18$

$= - 106$

II.

a)

$- \frac{12}{20} = - \frac{12 \div 4}{20 \div 4} = - \frac{3}{5} = - 0,6$

b)

$\frac{3}{5} = 0,6$

c)

$- \frac{6}{8} = - \frac{6 \div 2}{8 \div 2} = - \frac{3}{4} = - 0,75$

III.

a)

$= - 4(3m - 2) - ( - 5n + 8m) + (m + n)$

$= - 12m + 8 + 5n - 8m + m + n$

$= - 19m + 8 + 5n + n$

$= - 19m + 8 + 6n$

b)

$= ( - 9x + 3) \: . \: (x - 12) + (2x {}^{2} - 30)$

$= - 9x {}^{2} + 108x + 3x - 36 + 2x {}^{2} - 30$

$= - 7x {}^{2} + 108x + 3x - 36 - 30$

$= - 7x {}^{2} + 111x - 36 - 30$

$= - 7x {}^{2} + 111x - 66$

c)

$= (8x - 1) {}^{2} - (2x + 3) \: . \: (x - 5)$

$= 64x {}^{2} - 16x + 1 - (2x {}^{2} - 10x + 3x - 15)$

$= 64x {}^{2} - 16x + 1 - (2x {}^{2} - 7x - 15)$

$= 64x {}^{2} - 16x + 1 - 2x {}^{2} + 7x + 15$

$= 62x {}^{2} - 16x + 1 + 7x + 15$

$= 62x {}^{2} - 9x + 1 + 15$

$= 62x {}^{2} - 9x + 16$

Att. Makaveli1996