tìm x
A, (X+1)+(x+4)+(x+7)+...+(x+25)+(x+28)=155
b,(x+9)+(x-2)+(x+7)+(x-4)+(x+5)+(x-6)+(x+3)+(x-8)+(x+1)=95
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A, (X+1)+(x+4)+(x+7)+...+(x+25)+(x+28)=155
b,(x+9)+(x-2)+(x+7)
+(x-4)+(x+5)+(x-6)+(x+3)+(x-8)+(x+1)=95
A,(x+1)+(x+4)+(x+7)+...+(x+25)+(x+28)=155
x+1+x+4+x+7+...+x+25+x+28=155
x.[(28-1):3+1]+(1+4+7+...+25+28)=155
10.x+[(28+1).10:2]=155
10.x+145=155
A
<=>x+1+x+4+x+7+...+x+25+x+28=155
<=>10x.(1+4+7+10+13+16+19+22+25+28)=155
<=>10x.145 =155
<=>10x=155:145=\(\frac{31}{29}\)
x=\(\frac{31}{29}:10=\frac{31}{290}\)
Vậy x=\(\frac{31}{290}\)
a, (x + 9) + (x - 2) + (x + 7) + (x - 4) + (x + 5) + (x - 6) + (x + 3) + (x - 8) + (x + 1) = 95
x + 9 + x - 2 + x + 7 + x - 4 + x + 5 + x - 6 + x + 3 + x - 8 + x + 1 = 95
9x + 9 - 2 + 7 - 4 + 5 - 6 + 3 - 8 + 1 = 95
9x + 5 = 95
9x = 95 - 5
9x = 90
x = 90 : 9
x = 10
Vậy x = 10
b, {[(x : 2) - 1/2 ] : 4 - 1/4 } : 5 = 5 + 1/5
{[(x : 2) - 1/2 ] : 4 - 1/4 } : 5 = 26/5
{[(x : 2) - 1/2 ] : 4 - 1/4 } = 26/5 x 5
[(x : 2) - 1/2 ] : 4 - 1/4 = 26
[(x : 2) - 1/2 ] : 4 = 26 + 1/4
[(x : 2) - 1/2 ] : 4 = 105/4
(x : 2) - 1/2 = 105/4 x 4
(x : 2) - 1/2 = 105
x : 2 = 105 + 1/2
x : 2 = 211/2
x = 211/2 x 2
x = 211
Vậy x = 211
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???
\(\left(x+9\right)+\left(x-2\right)+\left(x+7\right)+\left(x-4\right)+\left(x+5\right)+\left(x-6\right)+\left(x+3\right)+\left(x-8\right)+\left(x+1\right)=95\)
\(x+9+x-2+x+7+x-4+x+5+x-6+x+3+x-8+x+1=95\)
\(\left(x\times9\right)+\left(9-2+7-4+5-6+3-8+1\right)=95\)
\(x\times9+5=95\)
\(x\times9=95-5\)
\(x\times9=90\)
\(x=90:9\)
\(x=10\)
(x + 9) + (x - 2) + (x + 7) + (x - 4) + (x + 5) + (x - 6) + (x + 3) + (x - 8) + (x + 1) = 95
x + 9 + x - 2 + x + 7 + x - 4 + x + 5 + x - 6 + x + 3 + x - 8 + x + 1
(x + x + x + x + x + x + x + x + x) + (9 - 8 + 7 - 6 + 5 - 4 + 3 - 2 + 1) = 95
9 × x + 5 = 95
9 × x = 95 - 5
9 × x = 90
x = 90 : 9
x = 10
a, (x + 1) + (x + 4) + ... + (x + 28) = 155
<=> (x + x + ... + x) + (1 + 4 + ... + 28) = 155
<=> 10x + 145 = 155
<=> 10x = 10
<=> x = 1
b, (x + 9) + (x - 2) + (x + 7) + (x - 4) + ... + (x - 8) + (x + 1) = 95
<=> (x + 9 + x + 7 + ... + x + 1) + (x - 2 + x - 4 + .. + x - 8) = 95
<=> (5x + 25) + (4x - 20) = 95
<=> (5x + 4x) + (25 - 20) = 95
<=> 9x + 5 = 95
<=> 9x = 90
<=> x = 10
@láo như cáo