5x×7×5x-1=875
Những câu hỏi liên quan
Tìm X
5x+1+ 6,5x+1 =875
(5+6,5)x = 875-1-1
11,5x = 873
x = 873:11,5
x = \(\frac{1746}{23}\)
Đúng 0
Bình luận (0)
1 TÌM x,biết
a,2^x-1+2^x+1=20
b,3^5x+1-5.3^5x-1=594
c,5^x+1+6.5^x+1=875
2Tìm x,y thuộc N
a,2^x+1.5^y=20^y
b,10^x : 5^y=20^y
Giups mik với nha!!!
a) 2x - 1 + 2x + 1 = 20
=> 2x : 2 + 2x . 2 = 20
=> 2x . 1/2 + 2x . 2 = 20
=> 2x.(1/2 + 2) = 20
=> 2x . 5/2 = 20
=> 2x = 20 : 5/2
=> 2x = 8
=> 2x = 23
=> x = 3
Đúng 0
Bình luận (0)
Bài 1: Rút gọn
A=(7-2x)(7+2x)+(2x+7)2
B=(4x-5)2-(2x-1)(8x-5)
C=(5x-3)2-2(5x-3)(5-5x)+(5x-5)2
D=(2a+3b-c)(2a-3b+c)-(4a2-9b2-c2)
A=(7-2x)(7+2x)+(2x+7)2
=49-4x2+4x2+28x+49
= 98+28x
B=(4x-5)2-(2x-1)(8x-5)
= 16x2-25-((8x(2x-1))-(5(2x-1)))
= 16x2-25-((16x2+8x)-(10x+5))
= 16x2-25-(16x2+8x-10x-5)
= 16x2-25-16x2-8x+10x+5
= -20+2x
Đúng 1
Bình luận (0)
Bài 1: Rút gọn
A=(7-2x)(7+2x)+(2x+7)2
B=(4x-5)2-(2x-1)(8x-5)
C=(5x-3)2-2(5x-3)(5-5x)+(5x-5)2
D=(2a+3b-c)(2a-3b+c)-(4a2-9b2-c2)
a) Ta có: \(A=\left(7-2x\right)\left(7+2x\right)+\left(2x+7\right)^2\)
\(=7-4x^2+4x^2+28x+49\)
\(=28x+56\)
b) Ta có: \(B=\left(4x-5\right)^2-\left(2x-1\right)\left(8x-5\right)\)
\(=16x^2-40x+25-\left(16x^2-10x-8x+5\right)\)
\(=16x^2-40x+25-16x^2+18x-5\)
\(=-22x+20\)
c) Ta có: \(C=\left(5x-3\right)^2-2\left(5x-3\right)\left(5-5x\right)+\left(5x-5\right)^2\)
\(=\left(5x-3\right)^2+2\cdot\left(5x-3\right)\left(5x-5\right)+\left(5x-5\right)^2\)
\(=\left(5x-3+5x-5\right)^2\)
\(=\left(10x-8\right)^2\)
\(=100x^2-160x+64\)
d) Ta có: \(D=\left(2a+3b-c\right)\left(2a-3b+c\right)-\left(4a^2-9b^2-c^2\right)\)
\(=\left[\left(2a+\left(3b-c\right)\right)\left(2a-\left(3b-c\right)\right)\right]-\left(4a^2-9b^2-c^2\right)\)
\(=4a^2-\left(3b-c\right)^2-4a^2+9b^2+c^2\)
\(=-9b^2+6bc-c^2+9b^2+c^2\)
=6bc
Đúng 2
Bình luận (0)
Tìm x biết
(5x-1)2-(5x-4)(5x+4)=7
`(5x-1)^2-(5x-4)(5x+4)=7`
`\Leftrightarrow 25x^2-10x+1-25x^2+16-7=0`
`\Leftrightarrow -10x+10=0`
`\Leftrightarrow x=1`
Đúng 0
Bình luận (0)
Bài 1: Tìm x, biết .
a. 5x( 12x + 7) - 3x ( 20x - 5) = -100
b. 5x( 2x - 7) + 2x ( 8 - 5x) = 5
a)\(60x^2+35x-60x^2+15x=100\)
35x+15x=100
50x=100 =>x=2
b)\(10x^2-35x+16x-10x^2=5\)
-35x+16x=5
-19x=5 =>x=-5/19
Đúng 0
Bình luận (0)
a)60x2+35x−60x2+15x=10060x2+35x−60x2+15x=100
35x+15x=100
50x=100
=>x=2
b)10x2−35x+16x−10x2=510x2−35x+16x−10x2=5
-35x+16x=5
-19x=5
=>x=-5/19
Đúng 0
Bình luận (0)
(5x-1)2 - (5x-4) (5x+4)=7
BT1: Tìm x biết.
a, (5x-1)(2x+7)-(x+1)(6x-5)=16
b, (10x+9).x-(5x-1).(2x+3)=8
c, (3x-5).(7-5x)+(5x+2).(3x+2)-2=0
d, x.(x+1).(x+6)-x3=5x
a. (3x - 1).(2x + 7) - (x + 1).(6x - 5) = 16
<=> 6x^2 + 19x - 7 - (6x^2 + x - 5) = 16
<=> 18x - 2 = 16
<=> 18x = 18
<=> x = 1
b. (10x + 9).x - (5x - 1).(2x + 3) = 8
<=> 10x^2 + 9x - (10x^2 + 13x - 3) = 8
<=> -4x + 3 = 8
<=> -4x = 5
<=> x = -5/4
c. (3x - 5).(7 - 5x) + (5x + 2).(3x - 2) - 2 = 0
<=> -15x^2 + 46x - 35 + 15x^2 - 4x - 4 - 2 = 0
<=> 42x - 41 = 0
<=> x = 41/42
Tìm x:
a ) (3x -5)^2 - (3x +2) (3x - 2) = 8
b ) (5x + 3) (3 - 5x) + (5x - 7) ( 5x - 7) = 1
∣5x+7∣∣∣+∣∣∣5x−1∣∣∣3.23(2y+1)2020+4
Đọc tiếp
∣5x+7∣∣∣+∣∣∣5x−1∣∣∣=3.23(2y+1)2020+4
5x+7+5x-1=(5x+5x)+(7-1)=10x+6
Đúng 0
Bình luận (0)