tìm x
x + 32 = 23 + 24
x= ???
x + 123 = 2314 + 1234
x = ????
Tìm GTLN hoặc GTLN:
a) `A = (5x^2 - 24x + 32)/(x^2 - 4x + 4)`
b) `B = ( 10x^2 + 24x + 15)/(x^2 + 2x + 1)`
\(A=\dfrac{4\left(x^2-4x+4\right)+\left(x^2-8x+16\right)}{x^2-4x+4}=4+\left(\dfrac{x-4}{x-2}\right)^2\ge4\)
\(A_{min}=4\) khi \(x=4\) (A max ko tồn tại)
\(B=\dfrac{6\left(x^2+2x+1\right)+\left(4x^2+12x+9\right)}{x^2+2x+1}=6+\left(\dfrac{2x+3}{x+1}\right)^2\ge6\)
\(B_{min}=6\) khi \(x=-\dfrac{3}{2}\)
B max ko tồn tại
Tìm GTLN của: `A = (x^2 - 24x + 32)/(x^2 - 4x + 4)`
Biểu thức này chỉ có max, ko có min
ĐKXĐ: ...
\(A=\dfrac{3x^2-72x+96}{3\left(x^2-4x+4\right)}=\dfrac{28\left(x^2-4x+4\right)-\left(25x^2-40x+16\right)}{3\left(x^2-4x+4\right)}=\dfrac{28}{3}-\dfrac{1}{3}\left(\dfrac{5x-4}{x-2}\right)^2\le\dfrac{28}{3}\)
\(A_{max}=\dfrac{28}{3}\) khi \(5x-4=0\Leftrightarrow x=\dfrac{4}{5}\)
tìm x
11, (x+3)3 = 125
12, (2x)4 = 16
13, 32 : (3x - 2) = 23
14, 20 - 2(x + 4) = 23
15, 14 ⋮(2.x+3)
16, 30- [4(x - 2)+15] = 3
17, 27 : ( x - 1)= 32
18, (10 + 2x) : 42011= 42013
19, (x + 5) ⋮(x +2)
20,[(8x - 12) : 4].33=36
mong các bạn giúp mình ^^
11: Ta có: \(\left(x+3\right)^3=125\)
\(\Leftrightarrow x+3=5\)
hay x=2
12: Ta có: \(\left(2x\right)^4=16\)
\(\Leftrightarrow x^4=1\)
hay \(x\in\left\{1;-1\right\}\)
11: Ta có:
hay x=2
12: Ta có:
4
13) 32:(3x-2)=2^3
32:(3x-2)=8
3x-2=32:8=4
3x=4+2=6
x=6:3=2
⇔x=2
Bài 1: Tìm x [GIÚPPPPPPPPPPPPPPPPPPP]
1) 5 – (10 – x) = 7
2) - 32 - (x – 5) = 0
3) -12 + (2x – 9) + x= 0
4) 11 + (15 - x) = 1
5) 4 - (27 - 3) = x - (13 - 4)
6) 8 - (x - 10) = 23 - (- 4 +12)
7) 105 – 5(10 – 5x) = -20
8) (x -1)(8-2x)(3x+123) = 0
9) (x2 - 25)(x+ 10) = 0
10) x(x2+5) = 0
\(1\)) \(5-\left(10-x\right)=7\)
\(10-x=5-7\)
\(10-x=-2\)
\(x=10-\left(-2\right)\)
\(x=12\)
\(2\)) \(-32-\left(x-5\right)=0\)
\(x-5=-32-0\)
\(x-5=-32\)
\(x=-32+5\)
\(x=-27\)
1)10-x=5-7
x=10-(-2)
x=12
2)x+5=0+32
x=32-5
x=27
3) -12+2x-9+x=0
-12+(2x+x-9)=0
3x-9=0+12
3x=12+9
x=21:3
x=7
4) 15-x=1-11
x=15-(-10)
x=25
5) 4-(27+3)=x-9
4-30=x-9
-26+9=x
x=-17
a)5. ( x + 35 ) = 515
b) (x+7):3=14c) 72:(x–15)=8
d) 19+(x+23)=50
e) (18–x) + 23 =29
f) 56–(x+14)=22g) (2x +1)–7=14
h) 3. (x+1)–32=67i) 70–5. (x–3)=45
j) 200–8. (2x+7)=112
k) 123–(x+4). 5 =38
\(a,\Rightarrow x+35=103\\ \Rightarrow x=68\\ b,\Rightarrow x+7=42\\ \Rightarrow x=35\\ c,\Rightarrow x-15=9\\ \Rightarrow x=24\\ d,\Rightarrow x+23=31\\ \Rightarrow x=8\\ e,\Rightarrow18-x=6\\ \Rightarrow x=12\\ f,\Rightarrow x+14=34\\ \Rightarrow x=20\\ g,\Rightarrow2x+1=21\\ \Rightarrow x=11\\ h,\Rightarrow3\left(x+1\right)=99\\ \Rightarrow x+1=33\Rightarrow x=32\\ i,5\left(x-3\right)=25\\ \Rightarrow x-3=5\\ \Rightarrow x=8\\ j,\Rightarrow8\left(2x+7\right)=88\\ \Rightarrow2x+7=11\Rightarrow x=2\\ k,\Rightarrow5\left(x+4\right)=85\\ \Rightarrow x+4=17\\ \Rightarrow x=13\)
Bài 1: Tìm x
a) x - 32 + 25 = 12 x 2
b) 24 + x - 3 = 21
c) x * 10 : 2 = 40
Bài 2 : Tính gía trị của biểu thức
a) 123 - 82 x 6
b) 458 - 125 + 23
c) 325 + 125 x 125 x 325
Bài 1:
a) x - 32 + 25 = 12 x 2
x- 32 +25 = 24
x -32 = -1
x = 31
b) 24 + x - 3 = 21
24+x = 24
x = 0
c) x * 10 : 2 = 40
x *10 = 80
x = 8
Bài 2:
a) 123 - 82 x 6= 123- 492= -369
b) 458 - 125 + 23= 333+23 = 356
c) 325 + 125 x 125 x 325= 325 + 5 078 450
Cái này giống như bài lớp 6 ý.
Bài 1 : Tìm x
a) x - 32 + 25 = 12 x 2
x - 32 + 25 = 24
x - 32 = 24 - 25
x - 32 = ( - 1 )
x = ( -1 ) + 32
x = 31
b) 24 + x - 3 = 21
24 + x = 21 + 3
24 + x = 24
x = 24 - 24
x = 0
c) x * 10 : 2 = 40
x * 10 = 40 x 2
x * 10 = 80
x = 80 : 10
x = 8
Bài 2: Tính giá trị của biểu thức
a) 123 - 82 x 6
123 - 492
-369
b) 458 - 125 + 23
333 + 23
356
c) 325 + 125 x 125 x 325
325 + 5078125
5078450
Bài 1:
a/\(x-32+25=12\cdot2\)
\(x-32+25=24\)
\(x-32=24-25=-1\)
\(x=\left(-1\right)+32=31\)
b/\(24+x-3=21\)
\(24+x=21+3=24\)
\(x=24-24=0\)
c/\(\frac{x\cdot10}{2}=40\)
\(x\cdot10=40\cdot2=80\)
\(x=\frac{80}{10}=8\)
Tìm x.
a. x + 2005 = 123 × 45
b. 1837 + x ÷ 15 = 486 × 23
a. x + 2005 = 123 × 45
x + 2005 = 5535
x = 5535 - 2005
x = 3530
b. 1837 + x ÷ 15 = 486 × 23
1837 + x ÷ 15 = 11178
x = 140115
tìm x
X + 123 -23 =100
x + 123 - 23 = 100
x + 123 = 123
x = 123 - 123
x = 0
tìm x
x+23=100 123+x=127
x+23=100 123+x=127
x = 100-23 x=127-123
x =77 x= 4
✔️ ✔️ ✔️
x + 23 = 100 123 + x = 127
x = 100 - 23 x = 127 - 123
x = 77 x = 4
x + 23= 100
x=100 - 23
x=77
123+x=127
x=127-123
x=4