Question

Calcule o valor numérico $8x^{2} + \frac{3}{4}x^{2} -5 para x= -1$

Answer 1

vamos lá...

$8 x^{2} + \frac{3}{4} x^{2} -5=~~~~~~~~para~~~x=-1 \\ \\ 8(-1)^2+ \frac{3}{4} (-1)^2-5= \\ \\ 8(+1)+ \frac{3}{4} (+1)-5= \\ \\ 8+ \frac{3}{4} -5= \\ \\ 3+ \frac{3}{4} = \frac{12+3}{4} = \frac{15}{4}$