Question

(7X - 5) • (3 X + 5)​

Answer 1

Resposta:

3e7333377272727777171711727w

Answer 2

Resposta:

5/7 e -5/3

Explicação passo a passo:

$(7x-5)(3x+5)\\=(7x*3x+7x*5)-(5*3x+5*5)\\=(21x^2+35x)-(15x+25)\\=21x^2+35x-15x-25\\=21x^2+20x-25$

Resolvendo a equação do segundo grau por bhaskara:

$=b^2-4ac$

$=20^2-4.21.(-25)\\=400+2100\\=2500$

$x=\frac{-20+/- \sqrt{2500} }{2*21}\\ x=\frac{-20+/- 50}{42}\\\\x'=\frac{-20+50 }{42}=\frac{30}{42}= \frac{5}{7}\\\\x''=\frac{-20-50 }{42}=\frac{-70 }{42}=\frac{-5}{3}$