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Toán Lớp 8: a/ (x – 2)2 – (x+3)2 – 4(x+1) = 5. b/ (2x – 3) (2x + 3) – (x – 1)2 – 3x(x – 5) = – 44

Home/ Toán Lớp 8: a/ (x – 2)2 – (x+3)2 – 4(x+1) = 5. b/ (2x – 3) (2x + 3) – (x – 1)2 – 3x(x – 5) = – 44

Toán Lớp 8: a/ (x – 2)2 – (x+3)2 – 4(x+1) = 5. b/ (2x – 3) (2x + 3) – (x – 1)2 – 3x(x – 5) = – 44

Ðan Khanh Tháng Tám 31, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: a/ (x – 2)2 – (x+3)2 – 4(x+1) = 5.
b/ (2x – 3) (2x + 3) – (x – 1)2 – 3x(x – 5) = – 44

Comments ( 2 )

tuminh25
31 Tháng Tám, 2022 at 2:27 sáng

Reply

a)(x-2)^2-(x+3)^2-4(x+1)=5

<=>x^2-4x+4-x^2-6x-9-4x-4=5

<=>-14x=14

<=>x=-1

Vậy x=-1

b)(2x-3)(2x+3)-(x-1)^2-3x(x-5)=-44

<=>4x^2-9-x^2+2x-1-3x^2+15x=-44

<=>17x=-34

<=>x=-2

Vậy x=-2
truonganhthi
31 Tháng Tám, 2022 at 2:27 sáng

Reply

a)

$(=) x^2 – 4x + 4 -(x^2 + 6x+9) -4x-4=5$

$(=) x^2 – 4x-x^2 – 6x – 9-4x=5$

$(=) -14x=5+9$

$(=) -14x=14$

$=) x=-1$

b)

$(=) (2x+3)^2 – (x^2-2x+1) – 3x^2 + 15x = -44$

$(=) 4x^2 – 9 – (x^2 – 2x+1) – 3x^2 + 15x=-44$

$(=) 4x^2 – 9-x^2 + 2x-1-3x^2 + 15x=-44$

$(=)-10+17x=-44$

$(=) 17x=-44+10$

$(=) 17x=-34$

$=) x=-2$

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