\(\left(2x-3\right)\left(x+1\right)+\left(4x^3-6x^2-6x\right):\left(-2x\right)=18\)

\(\Leftrightarrow2x^2+2x-3x-3-2x^2+3x+3=18\)

\(\Leftrightarrow x=9\)

Jdjđj

\(\dfrac{x^2-6x+15}{x^2-6x+11}=\sqrt{x^2-6x+18}\)

\(\Leftrightarrow1+\dfrac{4}{x^2-6x+11}=\sqrt{\left(x-3\right)^2+9}\)

Ta có: \(x^2-6x+11=\left(x-3\right)^2+2\ge2\)

\(\Rightarrow VT=1+\dfrac{4}{x^2-6x+11}\le1+\dfrac{4}{2}=3\)

\(VP=\sqrt{\left(x-3\right)^2+9}\ge3\)

D=xrk x=3

Kl: x=3

Đặt \(x^2-6x+18=t\)\(\left(t\ge9\right)\)

\(\Rightarrow\dfrac{t-3}{t-7}=\sqrt{t}\)

\(\Leftrightarrow t\sqrt{t}-7\sqrt{t}=t-3\)

\(\Leftrightarrow\left(\sqrt{t}\right)^3-t-7\sqrt{t}+3=0\)

\(\Leftrightarrow\left(\sqrt{t}-3\right)\left(t+2\sqrt{t}-1\right)=0\)

Ta Thấy :

\(t+2\sqrt{t}-1\) có 2 nghiệm là \(\left\{-\left(\sqrt{2}+1\right);\left(\sqrt{2}-1\right)\right\}\)đều nhỏ hơn 9

Nên \(\sqrt{t}=3\Leftrightarrow t=9\left(tm\right)\)

\(\Rightarrow x^2-6x+18=9\)

\(\Leftrightarrow x^2-6x+9=0\)

\(\Leftrightarrow\left(x-3\right)^2=0\Leftrightarrow x=3\)

Vậy Phương trình đã cho có nghiệm x = 3 .

[(6x-12):2-18]x3=18

 (6x-12):2-18   =18:3=6

 (6x-12):2        =6+18=24

  6x-12            =24x2=48

  6x                 =48+12=60

 Vậy x = 0

(6x-12):2-18=18 : 3

(6x-12):2-18= 6
(6x-12):2=6 +18

(6x-12):2=24

6x-12=24 . 2

6x-12=48

6x=48+12

6x = 60

x = 60 :6

x = 10

[(6x-12):2-18]x3=18

(6x-12):2-18=18:3=6

(6x-12):2=6+18=24

6x-12=24x2=48

6x=48+12=60

x=60:6

x=10

bai nay trang 10 trong sanh toan nang cao va cac chuyen de (dai so ) 9

Dòng 1 trang 29  có ghi 

X=3

rẤT TIẾC TRANG 28 BỊ MẤT KHÔNG BIẾT DOẠN ĐẦU THẾ NÀO?

Kinh mọi sách

Ta có: \(3618:\left(6x-33\right)=18\)

\(\Leftrightarrow6x-33=201\)

\(\Leftrightarrow6x=234\)

hay x=39

Đặt \(A=\sqrt{x^2-6x+36}+\sqrt{x^2-6x+64}=18\)

\(B=\sqrt{x^2-6x+64}-\sqrt{x^2-6x+36}\)

\(\Rightarrow A.B=\left(x^2-6x+64\right)-\left(x^2-6x+36\right)=28\)

mà \(A=18\Rightarrow B=\frac{28}{18}=\frac{14}{9}\)

\(\left(50-6x\right).18=2^3.3^2.5\)

\(\left(50-6x\right).18=8.9.5\)

\(\left(50-6x\right).18=72.5\)

\(\left(50-6x\right).18=360\)

\(\left(50-6x\right)=360\div18\)

\(50-6x=20\)

\(6x=50-20\)

\(6x=30\)

\(x=30\div6\)

\(x=5\)

\(\Rightarrow KL:\Rightarrow x=5\)

(50 - 6x) . 18 = 2³.3².5

(50 - 6x). 18 = 8.9.5

(50 - 6x) . 18 = 360

50 - 6x = 360 : 18

50 - 6x = 20

6x = 50 - 20

6x = 30

x = 30 : 6

x = 5

bài này có 2 cách lm nha mn