Question

tìm x biết a) (10 – 2x) ² = 25 – (-11).

b)-2(-x+5)-3(5-x)=4(2+x)

mình cần gấp lắm giúp mình mình tick

 

Answer 1

Lâu rồi mình ko giải, sai thì thôi nhé!

a) \(\left(10-2x\right)^2=25-\left(-11\right)\)'=

\(\Leftrightarrow\left(10-2x\right)^2=36\)

\(\Leftrightarrow\left(10-2x\right)^2=6^2\)

\(\Leftrightarrow\orbr{\begin{cases}10-2x=6\\10-2x=-6\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=10-6\\2x=10-\left(-6\right)\end{cases}\Leftrightarrow}\orbr{\begin{cases}2x=4\\2x=16\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=2\\x=8\end{cases}}}\)

Vậy \(x\in\left\{2;8\right\}\)

b) \(-2\left(-x+5\right)-3\left(5-x\right)=4\left(2+x\right)\)

\(\Leftrightarrow-2\left(5-x\right)-3\left(5-x\right)=4\left(2+x\right)\)

\(\Leftrightarrow-5\left(5-x\right)=4\left(2+x\right)\)

\(\Leftrightarrow-25+5x=8+4x\)

\(\Leftrightarrow5x-25=8+4x\)

\(\Leftrightarrow5x=8+4x+25\)

\(\Leftrightarrow5x=4x+33\)

\(\Leftrightarrow5x-4x=33\)

\(\Leftrightarrow1x=33\)

\(\Leftrightarrow x=33\)

Vậy \(x=33\)

Answer 2

a) (10 - 2x)² = 25 - (-11)

(10 - 2x)² = 36

(10 - 2x)² = 6²

=> 10 - 2x = 6

2x = 10 - 6

2x = 4

x =4:2

x=2

Vậy x = 2

b)-2(-x+5) - 3(5 - x) = 4(2+x)

2x - 10 - 15 +3x = 8 + 4x

2x - 25 + 3x = 8 +4x

2x + 3x - 4x = 8 + 25

5x - 4x = 33

x= 33

Vậy x = 33

Answer 3

Ta có :

(10 - 2x ) ² =25-(-11)

(10-2x)²=36

(10-2x)²=6²

10-2x=6

2x=10-6

2x=4

x=4:2

x=2

b) Ta có :

-2(-x+5)-3(5-x)=4(2+x)

(-2(-x))+(-2x5)-(-3x5)-(-3(x))=8+4x

2x+(-10)-(-15)-(-3x)=8+4x

2x+3x-10+15=8+4x

5x+(15-10)=8+4x

5x+5=8+4x

5x-4x=5+8

x=13