Question

EQUAÇÕES DO 2° GRAU
a) x.(x - 5) +10 = 4
b) 2x. (4x - 1) =21
c) x.(x-2) = 2.(x + 6)
d) x.(2x -1) +6 = 4.(x +1)

Answer 1

A) $x^{2} -5x+10-4:0$
$x^{2} -5x+6:0$

a:1  b:-5  c:6
$b^{2} -4.a.c$$(-5)^{2} -4.1.6$

25-24: 1
$\frac{-(-5)+- \sqrt{1} }{2.1}$$\frac{-b+- \sqrt{Δ} }{2a}$

$\frac{5+-1}{2}$
$x' \frac{5+1}{2} :3$

$x'' \frac{5-1}{2} :2$

B)2X.(4X-1);21

$8x^{2} -2x-21 a:8 b:-2 c:-21$

$b^{2} -4.a.c (-2)^{2} -4.8.(-21) 4+672 delta:676$

$\frac{-(-2)+- \sqrt{676} }{2.8}$

$\frac{2+- 26}{16}$

$x': \frac{28}{16}: \frac{7}{4}$

$x'' \frac{24}{16} : \frac{-3}{2}$


C) x(x-2):2(x+6)

$x^{2} -2x: 2x+12$

$x^{2} -2x-2x-12:0$

$x^{2} -4x-12:0$

a:1 b:-4 c:-12

Δ:$b^{2} -4.a.c$


$\frac{-(-4) \sqrt{64} }{2.1}$

$x:\frac{4+-8}{2}$

$x': \frac{4+8}{2} : \frac{12}{2} :6$

$x'': \frac{4-8}{2} : -\frac{4}{2} : -2$