Question

determina as raízes das equação

$(x - 7)(x - 3) + 10x = 30$
${6}x {}^{2} - x - 5 = 0$
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Answer 1

Resposta:

$x^{2} -3x-7x+21 +10x=30\\x^{2} -10x+21+10x-30=0\\x^{2} -9=0\\x^{2} =9\\x=\sqrt{9}\\ x=3$

$6x^{2} -x-5=0$

Δ=$b^{2} -4.a.c$

Δ=$-1^{2} -4.6.(-5)</p><p>Δ=1+120</p><p>Δ=121</p><p>x=[tex]\frac{-b±\sqrt{Δ} }{2.a}$

x=$\frac{-(-1)±\sqrt{121} }{2.6}$

x=$\frac{1±121}{12}$

x`=$\frac{1-121}{12} =\frac{-120}{12} =-10$

x``=$\frac{1+121}{12} =\frac{122}{12}$