5x - 49 +2x = 0
5x+2x=0+49
7x=49
x=49 : 7
Vậy x=7
5x-49+2x=0
(5x+2x)-49=0
7x-49=0
=>7x=49
x=7 vì 7x7=49
1,-15(x+2)+7(2x-3)
2,x^2+2x=0
3,(-2x)(-4x)+28=100
4,(2x-5)^2-49=0
5,/x-5/+/y-3/=1
6,3×(x-2)-6(x-5)=2(5-2x)
7, 5x ×(-x)^2+1=0
8,4x^3=4x
Bài 1: Tìm x biết :
a) (x+2)^2 - (3x-7)^2=0
b) (4x+1) -(5x-3)^2=0
c) 25(x-3)^2 - 49(2x+1)^2=0
d) 9(3x-2)^2=121(1-4x)^2
e) (x-5/4)^2=(5x+1/2)^2
bài 1 :tìm x,y biết
a) (5x+1)=\(\dfrac{36}{49}\) b) (x-2/9) = (2/3) c)(8x-1) 2x+1= 5^2 x+1
d) (x-3,5)^x+(y - 1/10)^4=0
GIÚP E!
Tìm x:
a) 7^5x : 49 = 7^28
b)5^2x . 5^14 = 5^30
49.(2x+1)^2:25-49=0
1) 7x.49=790
2) 2x.4=128
3) 3x-1=24.5
4) 3x+15=42
5) 4.2x-3=125
6) 5x=515:53
7) 4x=415:16
8) 7x=720:710
9) 11x=1111:11
10) 315.3x=330
11) 10+2x=45:43
12) 20+5x=55:53
13) 4x-20=25:22
14) 15+2x=380:377
Chu y: dau "." la dau nhan.
1. Chứng minh rằng:
a. (a-b)-(c-d) = (a+d)-(b+c)
b. (a+b)-(a-b)+(a-c)-(a+c) = 2(b-c)
c. (b+b-c)+(a-b+c)-(b+c-a)-(a-b-c) = b+a
2. Tìm x, biết:
a. (-x2 - 1).(-3x+15) = 0
b. -2x-5x = -49
c. (3x2 -27).(x-7) = 0
d. (-4x-20).(9-2x) = 0
Tìm các số nguyên x,y sao cho:
a)\(x^2+5x+7⋮x+2\)
b)\(\left(x^2+7\right)\left(x^2-49\right)< 0\)
c)\(\left(x^2+7\right)\left(x^2-49\right)< 6\)
d)\(\left(2x-1\right)\left(2y+1\right)=-35\)
a,( 2x-2)^3=8
b,7^x+2=49^5:7^9
c,(5x-2)^2=10^3:10^4
