\(\Leftrightarrow x^2+6x+8-x^2=7\\ \Leftrightarrow6x=-1\Leftrightarrow x=-\dfrac{1}{6}\)

(x + 4)(x+2) - x² =7

x²+ 2x + 4x + 8 - x² = 7

6x + 8 = 7

6x = 7 - 8 = -1

=> x = \(\dfrac{-1}{6}\)

-12

-12

f(-5)=25-2=23

a) \(=x\left(x-5\right)+\left(x-5\right)^2=\left(x-5\right)\left(x+x-5\right)=\left(x-5\right)\left(2x-5\right)\)

b) \(=x^2-2.x.10+10^2=\left(x-10\right)^2\)

c) \(=x\left(x+3\right)+2\left(x+3\right)=\left(x+3\right)\left(x+2\right)\)

\(i)4^8:x=4^6\\ x=4^8:4^6\\ x=4^2\\ k)12x-33=3^5\\ 12x-33=243\\ 12x=243+3\\ 12x=276\\ x=276:12\\ x=23\\ l)\left(5x+335\right):2=20^2\\ \left(5x+335\right):2=400\\ 5x+335=400.2\\ 5x+335=800\\ 5x=800-335\\ 5x=465\\ x=465:5\\ x=93\) 

\(m)\left(x^2-10\right):5=3\\ x^2-10=3.5\\ x^2-10=15\\ x^2=15+10\\ x^2=25\\ x^2=5^2\\ 740:\left(x+10\right)=10^2-2.13\\ 740:\left(x+10\right)=100-26\\ 740:\left(x+10\right)=74\\ x+10=740:74\\ x+10=10\\ x=10-10\\ x=0.\)

i) 4⁸:x=4⁶

<=> x = 4⁸ : 4⁶ = 4² = 16

k)12x-33=3⁵

<=> x = (3⁵ + 33) : 12 = 23

l)(5x+335):2=20²

<=> x = (20² x 2 - 335) : 5 = 93

m)(x²-10):5=3

<=> x² = 3 x 5 + 10 = 25

<=> x = 5 hoặc x = -5

740:(x+10)=10²-2.13

<=> x = 740 : (10² - 2.13) - 10 = 0

a,4^8:X=4^6

X=4^8:4^6

X=4^2

b,12x-33=3^5

12x-33=243

12x=243+33

12x=276

12*X=276

X= 276:12

x=23

c,(5x+335):2=20^2

(5x+335):2=400

(5x+335)=400*2

(5x+335)=800

5*x+335=800

5*x=800-335

5*x=465

x=465:5

x=93

d, (x^2-10):5=3

x^2-10=3*5

x^2-10=15

x^2=15+10

x^2=25

x^2=5^2

vậy x=5

e,740:(x+10)=10^2 - 2*13

740:(x+10)=10^2-26

740:(x+10)=100-26

740:(x+10)=74

x+10=740:74

x+10=10

x=10-10

x=0

nhớ tik cho mik nhé

a: \(A=x^3+3x^2-5x-15+x^2-x^3+4x-4x^2\)

\(=-x-15\)

\(=-\left(-1\right)-15=1-15=-14\)

a: Ta có: \(A=x^2-20x+101\)

\(=x^2-20x+100+1\)

\(=\left(x-10\right)^2+1\ge1\forall x\)

Dấu '=' xảy ra khi x=10

\(x^2-30=34\)

\(x^2=34+30\)

\(x^2=64=8^2=\left(-8\right)^2\)

Vậy \(x=8^2\) hoặc \(x=\left(-8\right)^2\)