(x-2) mũ 3 -(x-3).(x mũ 2 +3x +9)+6.(x+1) mũ 2 =15
tìm x
(x-2) mũ 3 -(x-3).(x mũ 2 +3x +9)+6.(x+1) mũ 2 =15 tìm x
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(x-2) mũ 3 -(x-3).(x mũ 2 +3x +9)+6.(x+1) mũ 2 =15
tìm x
Helga
$(x-2)^3-(x-3)(x^2+3x+9)+6(x-1)^2=15_{}$
$⇔x^3-6x^2+12x-8-(x^3-27)+6(x^2+2x+1)=15_{}$
$⇔x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=15_{}$
$⇔24x+25=15_{}$
$⇔24x=-10_{}$
$⇔x=-\frac{5}{12}_{}$
RI SƠ
Đáp án:
Giải thích các bước giải:
(x-2)³-(x-3)(x²+3x+9)+6(x+1)²=15
⇒x³-6x²+12x-8-(x³-27)+6(x²+2x+1)=15
⇒x³-6x²+12x-8-x³+27+6x²+12x+6=15
⇒24x+25=15
⇒24x=15-25=-10
⇒x=-5/12