Toán (x-2) mũ 3 -(x-3).(x mũ 2 +3x +9)+6.(x+1) mũ 2 =15 tìm x 12/07/2021 By Mackenzie (x-2) mũ 3 -(x-3).(x mũ 2 +3x +9)+6.(x+1) mũ 2 =15 tìm x
$(x-2)^3-(x-3)(x^2+3x+9)+6(x-1)^2=15_{}$ $⇔x^3-6x^2+12x-8-(x^3-27)+6(x^2+2x+1)=15_{}$ $⇔x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=15_{}$ $⇔24x+25=15_{}$ $⇔24x=-10_{}$ $⇔x=-\frac{5}{12}_{}$ Trả lời
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 Trả lời
$(x-2)^3-(x-3)(x^2+3x+9)+6(x-1)^2=15_{}$
$⇔x^3-6x^2+12x-8-(x^3-27)+6(x^2+2x+1)=15_{}$
$⇔x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=15_{}$
$⇔24x+25=15_{}$
$⇔24x=-10_{}$
$⇔x=-\frac{5}{12}_{}$
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