bai 1tim x
x+3=15
x-7+3=25
x-3-6=-4
26-x+9=-13
Ban nao dung minh se tich
Bai 1Tim nguyen to a de 4a+11 la so nguyen to nho hon 30
Bai 2 cac so sau la so nguyen to hay so hop so:
a=1*3*5*7*....*13+20
b=147*247*347-13
Bai 1
vì (30-11):4=4.75 nen a <5
nguyên tố bé hơn 5 chỉ có 2 và 3 nên a =2;3
Vậy a ={2;3}
bai 1tim x bet
a) 2/3 .x=6
b) x. -5/7 =2/3+-3/4
bai 2)
mot nguoi di xe dap quang duong 8km mat 2/3 gio
hoi:
a) trong 1 gio nguoi do di duoc bao nhieu kilomet?
b) biet quang duong dai 36km , hoi nguoi do di mat thoi gian bao lau
Bài 1 : Tìm x biết :
a) 2/3. x = 6
x = 6 : 2/3
x = 9
Vậy x = 9
b) x . -5/7 = 2/3 + -3/4
x . -5/7 = -1/12
x = -1/12 : (-5/7)
x = 7/60
Vậy x = 7/60
bài 2 tớ ko biết
lam giup minh bai 2 di ma cac ban than iu ^ -- ^
1Tim x biet
\(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
\(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
\(\Rightarrow\frac{x+1}{9}+1+\frac{x+2}{8}+1=\frac{x+3}{7}+1+\frac{x+4}{6}+1\)
\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}=\frac{x+10}{7}+\frac{x+10}{6}\)
\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}-\frac{x+10}{7}-\frac{x+10}{6}=0\)
\(\Rightarrow\left(x+10\right)\left(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\right)=0\)
\(\Rightarrow x+10=0\) vì \(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\ne0\)
\(\Rightarrow x=-10\)
=>\(\frac{x+1}{9}\)+1+\(\frac{x+2}{8}\)+1=\(\frac{x+3}{7}\)+1+\(\frac{x+4}{6}\)+1
=>\(\frac{x+10}{9}\)+ \(\frac{x+10}{8}\)- \(\frac{x+10}{7}\)- \(\frac{x+10}{6}\)= 0
=>(x+10)x(\(\frac{1}{9}\)+ \(\frac{1}{8}\)+ \(\frac{1}{7}\)+\(\frac{1}{6}\))=0
=>x+10=0
=>x= -10
\(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
\(\frac{x+1}{9}+1+\frac{x+2}{8}+1=\frac{x+3}{7}+1+\frac{x+4}{6}+1\)
\(\frac{x+10}{9}+\frac{x+10}{8}=\frac{x+10}{7}+\frac{x+10}{6}\)
\(\frac{x+10}{9}+\frac{x+10}{8}-\frac{x+10}{7}-\frac{x+10}{6}=0\)
\(\left(x+10\right)\left(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\right)=0\)
Vì \(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\ne0\)nên x +10 = 0
x = -10.
bài 9; tìm x
1, 3x( x - 7) 2x - 14 = 0
2, x mũ 3 + 3x mũ 2 - ( x + 3 )= 0
3, 15x - 5 + 6x mũ 2 - 2x =0
4, 5x - 2 - 25x mũ 2 + 10x = 0
Tìm x biết
a) \(\dfrac{5}{3}\sqrt{15x}-\sqrt{15x}-2=\dfrac{1}{3}\sqrt{15x}\)
b) \(\sqrt{16x+16}-\sqrt{9x+9}+\sqrt{4x+4}+\sqrt{x+1}=16\)
c ) \(\sqrt{4x+20}-3\sqrt{5+x}+\dfrac{4}{3}\sqrt{9x+45}=6\)
d) \(\sqrt{25x-25}-\dfrac{15}{2}\sqrt{\dfrac{x-1}{9}}=6+\sqrt{x+1}\)
e ) \(\sqrt{4x^2+4x+1}=1\)
\(\sqrt{16x+16}-\sqrt{9x+9}+\sqrt{4x+4}+\sqrt{x+1}=16\)
\(\Leftrightarrow4\sqrt{x+1}-3\sqrt{x+1}+2\sqrt{x+1}+\sqrt{x+1}=16\)
\(\Leftrightarrow4\sqrt{x+1}=16\)
\(\Leftrightarrow\sqrt{x+1}=4\)
<=> x + 1 = 16
<=> x = 15 (nhận)
~ ~ ~
\(\sqrt{4x+20}-3\sqrt{5+x}+\dfrac{4}{3}\sqrt{9x+45}=6\)
\(\Leftrightarrow2\sqrt{x+5}-3\sqrt{x+5}+4\sqrt{x+5}=6\)
\(\Leftrightarrow3\sqrt{x+5}=6\)
\(\Leftrightarrow\sqrt{x+5}=2\)
<=> x + 5 = 4
<=> x = - 1 (nhận)
tính tan40°×tan45°×tan50°
#Help me -.-
\(x^9-15x^8+15x^7-15x^6+15x^5-15x^4+15x^3-15x^2+15x-15\)
Bai 1Tim x
a)(x+1)+(x+2)+(x+3)+...+(x+28)=462
b)890:x=35 dư 15
Phân tích đa thức thành nhân tử
a) x^8+ x^7+ 1
b) 8x^4- 4x^3+ 2x^2+ 9x- 45
c) 16x^4- 16x^3+ 7x^2+ 9x- 9
d) 24x^4- 4x^3- 158x^2+ 25x+ 50
e) 2x^3- x^2- 15x- 22x+ 8
Tính giá trị của biểu thức: P(x)=\(\left(x^3+15x-25\right)^{2019}\) với x=\(\sqrt[3]{13-7\sqrt{6}}+\sqrt[3]{13+7\sqrt{6}}\)
giải giúp mình với
\(x=\sqrt[3]{13-7\sqrt{6}}+\sqrt[3]{13+7\sqrt{6}}\Rightarrow x^3=26-15x\)
\(x^3+15x-25=1\Rightarrow\left(x^3+15x-25\right)^{2013}=1\)
Vậy P(x)=1 với .....