Tìm X biết:
a,-7.(5-X)-2(X-10)=15
b,10(X-7)-8(X+5)=6(-5)+24
tìm X biết:
a,-7.(5-X)-2.(X-10)=15
b,10.(X-7)-8.(X+5)=6.(-5)+24
a -7.(5-x) -2.(x-10)=15
= -35+7x-2x+20=15=5x=30
5x=30
x=6
b 10.(x-7)-8.(x+5)=6.(-5)+24
=10x-70-8x-40= -30+24
=10x-8x = -30+24+70+40
2x = 104
x = 104:2
x = 52
\(a)-7\left(5-x\right)-2\left(x-10\right)=15\)
\(\Rightarrow-35+7x-2x+20=15\)
\(\Rightarrow-35+20+7x-2x=15\)
\(\Rightarrow-15+5x=15\)
\(\Rightarrow5x=30\Rightarrow x=6\)
\(b)10\left(x-7\right)-8\left(x+5\right)=6\left(-5\right)+24\)
\(\Rightarrow10x-70-8x-40=-30+24\)
\(\Rightarrow10x-8x-70-40=-6\)
\(\Rightarrow2x-110=-6\)
\(\Rightarrow2x=104\Rightarrow x=52\)
Vậy\(a)x=6b)x=52\)
Bài toán 3 : Tìm x, biết.
a. 2(x – 5) – 3(x + 7) = 14 b. 5(x – 6) – 2(x + 3) = 12
c. 3(x – 4) – (8 – x) = 12 d. -7(3x – 5) + 2(7x – 14) = 28
e. 5(3 – 2x) + 5(x – 4) = 6 – 4x f. -5(2 – x) + 4(x – 3) = 10x – 15
g. 2(4x – 8) – 7(3 + x) = |-4|(3 – 2) h. 8(x – |-7|) – 6(x – 2) = |-8|.6 – 50
k. -7(5 – x) – 2(x – 10) = 15 l. 4(x – 1) – 3(x – 2) = -|-5|
m. -4(x + 1) + 89x – 3) = 24 n. 5(x – 30 – 2(x + 6) = 9
o. -3(x – 5) + 6(x + 2) = 9 p. 7(x – 9) – 5(6 – x) = – 6 + 11x
q. 10(x – 7) – 8(x + 5) = 6.(-5) + 24
nhiều quá :((
\(a,2\left(x-5\right)-3\left(x+7\right)=14\)
\(2x-10-3x-21=14\)
\(-x-31=14\)
\(-x=45\)
\(x=45\)
\(b,5\left(x-6\right)-2\left(x+3\right)=12\)
\(5x-30-2x-6=12\)
\(3x-36==12\)
\(3x=48\)
\(x=16\)
\(c,3\left(x-4\right)-\left(8-x\right)=12\)
\(3x-12-8+x=0\)
\(4x-20=0\)
\(4x=20\)
\(x=5\)
Cố nốt nha bn !
cảm ơn, bn nha:)))
mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???
d, \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)
\(\Leftrightarrow-21x+35+14x-28=28\Leftrightarrow-7x=21\Leftrightarrow x=-3\)
e, \(5\left(3-2x\right)+5\left(x-4\right)=6-4x\)
\(\Leftrightarrow15-6x+5x-20=6-4x\Leftrightarrow-5-x=6-4x\)
\(\Leftrightarrow-11+3x=0\Leftrightarrow x=\frac{11}{3}\)
f, \(-5\left(2-x\right)+4\left(x-3\right)=10x-15\)
\(\Leftrightarrow-10+5x+4x-12=10x-15\Leftrightarrow-22+9x=10x-15\)
\(\Leftrightarrow-7-x=0\Leftrightarrow x=-7\)
Tìm x, biết:
a) \(x:\dfrac{6}{13}=\dfrac{13}{7}\) b) \(\dfrac{4}{7}.x-\dfrac{2}{3}=\dfrac{1}{5}\) c) \(\left(\dfrac{3}{10}-x\right):\dfrac{2}{5}=\dfrac{3}{5}\) d) \(\dfrac{2}{3}.x-\dfrac{7}{6}=\dfrac{5}{2}\)
a) \(x:\dfrac{6}{13}=\dfrac{13}{7}\\ \Rightarrow x=\dfrac{13}{7}.\dfrac{6}{13}\\ \Rightarrow x=\dfrac{6}{7}\)
b) \(\dfrac{4}{7}.x-\dfrac{2}{3}=\dfrac{1}{5}\\ \Rightarrow\dfrac{4}{7}.x=\dfrac{13}{15}\\ \Rightarrow x=\dfrac{91}{60}\)
c) \(\left(\dfrac{3}{10}-x\right):\dfrac{2}{5}=\dfrac{3}{5}\\ \Rightarrow\dfrac{3}{10}-x=\dfrac{6}{25}\\ \Rightarrow x=\dfrac{3}{50}\)
d) \(\dfrac{2}{3}x-\dfrac{7}{6}=\dfrac{5}{2}\\ \Rightarrow\dfrac{2}{3}x=\dfrac{11}{3}\\ \Rightarrow x=\dfrac{11}{2}\)
\(a,\)\(x:\dfrac{6}{13}=\dfrac{13}{7}\)
\(x=\dfrac{13}{7}.\dfrac{6}{13}\)
\(x=\dfrac{6}{7}\)
b,\(\dfrac{4}{7}.x-\dfrac{2}{3}=\dfrac{1}{5}\)
\(\dfrac{4}{7}.x=\dfrac{1}{5}+\dfrac{2}{3}\)
\(\dfrac{4}{7}.x=\dfrac{3}{15}+\dfrac{10}{15}\)
\(\dfrac{4}{7}.x=\dfrac{13}{15}\)
\(x=\dfrac{13}{15}:\dfrac{4}{7}\)
\(x=\dfrac{13}{15}.\dfrac{7}{4}\)
\(x=\dfrac{91}{60}\)
a: Ta có: \(x:\dfrac{6}{13}=\dfrac{13}{7}\)
\(\Leftrightarrow x=\dfrac{13}{7}\cdot\dfrac{6}{13}\)
hay \(x=\dfrac{6}{7}\)
b: Ta có: \(\dfrac{4}{7}x-\dfrac{2}{3}=\dfrac{1}{5}\)
\(\Leftrightarrow x\cdot\dfrac{4}{7}=\dfrac{13}{15}\)
hay \(x=\dfrac{91}{60}\)
7 x 6 + 7 x 5 + 7 x 2 8 x 3 + 8 x 4 + 24 5 x 5 + 10 + 5 x 3
\(7*(6+5+2)=7*13=91\)
\(8*(3+4+3)=8*10=80\)
\(5*(5+2+3)=5*10=50\) nhé
7 x 6 + 7 x 5 + 7 x 2
=7 x (6+5+2)=7 x 13=91
8 x 3 + 8 x 4 + 24
=8 x (3+4) + 24=8 x 7 +24 =56 + 24=80
5 x 5 + 10 + 5 x 3
=5 x (10+3)=5 x 13=65
7∗(6+5+2)=7∗13=917∗(6+5+2)=7∗13=91
8∗(3+4+3)=8∗10=808∗(3+4+3)=8∗10=80
5∗(5+2+3)=5∗10=505∗(5+2+3)=5∗10=50
Bài 1: thực hiệ phép tính:
a) 555 : 5 + 225 : 15
b)95 - 5 . (30 - 2.7) + 10
c)65 : 63 + 5 . 32
d)-3 > x > 4
Bài 2 : Tìm x, biết:
a)6 . (x - 7) = 63
b)4 . (3x - 4) - 2 = 2 . 32
c)x ⋮ 12 và 100 < x < 150
Bài 3 : Tính diện tích hình thang cân ABCD biết đáy AB = 10 cm, đáy CD = 25cm, chiều cao AH = 7cm.
Ai bt bài này thù giúp mk nha .
Bài 2:
a: \(\Leftrightarrow x-7=36\)
hay x=43
1/ 10(X-7)-8(X+5)=6(-5)+24
2/ 8(X-|-7|)-6(X-2)=|-8|.6-50
3/ 2(4X-8)-7(3+X)=|-4|(3-2)
4/ 12(X-4)=6(x-2)-16(X+3)=7|-4|
5/ 4(X-5)-7(5-X)+10(5-X)=-3
bn nào giải giúp mik vs nha:)))
1/ 10(X-7)-8(X+5)=6(-5)+24
10x - 70 - 8x - 40 = -30 +24
2x - 110 = -6
2x = 104
x=52
2/ 8(X-|-7|)-6(X-2)=|-8|.6-50
8(x - 7) - 6(x-2) = 8.6 - 50
8x - 56 - 6x +12 =48 -50
2x - 44 = -2
2x = 42
x=21
3/ 2(4X-8)-7(3+X)=|-4|(3-2)
8x-16 - 21 - 7x = 4.1
x-37=4
x=41
4/ 12(X-4)=6(x-2)-16(X+3)=7|-4|
12x - 48 = 6x - 12 - 16x -48 =7.4
12x - 48 = 28
12x=76
x=19/3
5/ 4(X-5)-7(5-X)+10(5-X)=-3
4x - 20 -35 +7x + 50 -10x = -3
x - 5 = -3
x = -2
Chúc bạn học tốt!
Tìm x biết:
a) 2(4x-8)-7(3+x)=|-4|.(3-2)
b) 8(x-|-7|)-6(x-2)=|-8|.6-50
c) -7(5-x)-2(x-10)=15
d) 4(x-1)-3(x-2)=-|-5|
e) -4(x+1)+(89x-3)=24
f) 5(x-30-2(x+6)=9
g) -3(x-5)+6(x+2)=9
h) 7(x-9)-5(6-x)=-6+11x
k) 10(x-7)-8(x+5)=6.(-5)+24
=> THANKS TRƯỚC !!!
a) 2(4x-8)-7(3+x)=|-4|.(3-2)
8x-16-21-7x=4
8x-7x=4+16+21
x=41
Vậy x=41
b) 8(x-|-7|)-6(x-2)=|-8|.6-50
8x-56-6x+12=8.6-50
8x-6x=48-50+56-12
2x=42
x=42:2
x=21
Vậy x=21
c) -7(5-x)-2(x-10)=15
-35+7x-2x+20=15
7x-2x=15+35-20
5x=30
x=30:5
x=6
Vậy x=6
d) 4(x-1)-3(x-2)=-|-5|
4x-4-3x+6=-5
4x-3x=-5+4-6
x=-7
Vậy x=-7
e) -4(x+1)+(89x-3)=24
-4x-4+89x-3=24
-4x+89x=24+4+3
85x=31
x=31/85
f) 5(x-30)-2(x+6)=9
5x-150-2x-12=9
5x-2x=9+150+12
3x=171
x=171:3
x=57
Vậy x=57
g) -3(x-5)+6(x+2)=9
-3x+15+6x+12=9
-3x+6x=9-15-12
3x=-18
x=-18:3
x=-6
Vậy x=-6
h) 7(x-9)-5(6-x)=-6+11x
7x-63-30+5x=-6+11x
7x+5x-11x=-6+62+30
x=86
Vậy x=86
k) 10(x-7)-8(x+5)=6.(-5)+24
10x-70-8x-40=-30+24
10x-8x=-30+24+70+40
2x=104
x=104:2
x=52
Vậy x=52
Câu 30.Nếu x + 1/8 = 2/x + 1 thì giá trị của x bằng
A.5
B.-3
C.5 hoặc -3
D.3 hoặc -5
Câu 31.Kết quả phép tính -7/15 x 5/8 x 15/-7 x (-16)
A.7/15
B.5/8
C.15/-7
D.-10
Câu 30.Nếu x + 1/8 = 2/x + 1 thì giá trị của x bằng
A.5
B.-3
C.5 hoặc -3
D.3 hoặc -5
Câu 31.Kết quả phép tính -7/15 x 5/8 x 15/-7 x (-16)
A.7/15
B.5/8
C.15/-7
D.-10
Câu 30:
\(\dfrac{x+1}{8}=\dfrac{2}{x+1}\)
=>\(\left(x+1\right)^2=2\cdot8=16\)
=>\(\left[{}\begin{matrix}x+1=4\\x+1=-4\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)
=>Chọn D
Câu 31:
\(-\dfrac{7}{15}\cdot\dfrac{5}{8}\cdot\dfrac{15}{-7}\cdot\left(-16\right)\)
\(=\dfrac{5}{8}\cdot\left(-16\right)=-10\)
=>Chọn D