(x-6)(7-x)=0
Tìm xÎ Z, biết:
a) x + 20 = 7 b) x – 12 = -18 c) ( 9 – x).(x + 6) = 0 d) (-x).(x – 4) = 0 e) 6 – x = 13 – (3 –14) g) và -7 ≤ x < 7 h) và -21 < x ≤ 7
a: =>x=7-20=-13
b: =>x=-18+12=-6
c: =>x=9 hoặc x=-6
d: =>x=0 hoặc x=4
e: =>6-x=13-3+14=24
=>x=-18
Câu g và h đề thiếu rồi bạn
1) (x+6)(3x-1)+x+6=0
2) (x+4)(5x+9)-x-4=0
3)(1-x)(5x+3)÷(3x-7)(x-1)
4)2x (2x-3)=(3-2x)(2-5x)
5)(2x-7)^2-6(2x-7)(x-3)=0
6)(x-2)(x+1)=x^2-4
7) x^2-5x+6=0
8)2x^3+6x^2=x^2+3x
9)(2x+5)^2=(x+2)^2
1) (x+6)(3x-1)+x+6=0
⇔(x+6)(3x-1)+(x+6)=0
⇔(x+6)(3x-1+1)=0
⇔3x(x+6)=0
2) (x+4)(5x+9)-x-4=0
⇔(x+4)(5x+9)-(x+4)=0
⇔(x+4)(5x+9-1)=0
⇔(x+4)(5x+8)=0
3)(1-x)(5x+3)÷(3x-7)(x-1)
=\(\frac{\left(1-x\right)\left(5x+3\right)}{\left(3x-7\right)\left(x-1\right)}=\frac{\left(1-x\right)\left(5x+3\right)}{\left(7-3x\right)\left(1-x\right)}=\frac{\left(5x+3\right)}{\left(7-3x\right)}\)
Tính nhẩm:
7 x 3 =
7 x 8 =
7 x 2 =
7 x 1 =
7 x 5 =
7 x 6 =
7 x 10 =
0 x 7 =
7 x 7 =
7 x 4 =
7 x 9 =
7 x 0 =
7 x 3 = 21
7 x 8 = 56
7 x 2 = 14
7 x 1 = 7
7 x 4 = 35
7 x 6 = 42
7 x 10 = 70
0 x 7 = 0
7 x 7 = 49
7 x 4 = 28
7 x 9 = 63
7 x 0 = 0
7x3=21
7x8=56
7x2=14
7x1=7
7x5=35
7x6=42
7x10=70
0x7=0
7x7=49
7x4=28
7x9=63
7x0=0
Tính nhẩm:
7 x 1 =
7 x 8 =
7 x 6 =
7 x 5 =
7 x 2 =
7 x 9 =
7 x 4 =
0 x 7 =
7 x 3 =
7 x 7 =
7 x 0 =
7 x 10 =
7 x 1 = 7
7 x 8 = 56
7 x 6 = 42
7 x 5 = 35
7x 2 = 14
7 x 9 = 63
7 x 4 = 28
0 x 7 = 0
7x 3 = 21
7 x 7 = 49
7 x 0 = 0
7 x 10 = 70
Tính nhẩm
7 x 2 = ..... 7 x 5 = ..... 7 x 6 = ..... 0 x 7 = .....
7 x 4 = ..... 7 x 3 = ..... 7 x 9 = ..... 7 x 0 = .....
7 x 8 = ..... 7 x 1 = ..... 7 x 10 = ..... 1 x 7 = .....
7 x 2 = 14 7 x 5 = 35 7 x 6 = 42 0 x 7 = 0
7 x 4 = 28 7 x 3 = 21 7 x 9 = 63 7 x 0 = 0
7 x 8 = 56 7 x 1 = 7 7 x 10 =70 1 x 7 = 7
Viết số thích hợp vào chỗ chấm :
7 x 3 = ... 7 x 1 = ... 7 x 6 = ... 7 x 0 = ...
3 x 7 = ... 1 x 7 = ... 6 x 7 = ... 7 x 7 = ...
7 x 3 = 21 7 x 1 = 7 7 x 6 = 42 7 x 0 = 0
3 x 7 = 21 1 x 7 = 7 6 x 7 = 42 7 x 7 = 49
Tính nhẩm
6 x 1 = ..... 6 x 9 = .....
6 x 2 = ..... 6 x 8 = .....
6 x 3 = ..... 6 x 7 = .....
6 x 4 = ..... 0 x 6 = .....
6 x 5 = ..... 6 x 0 = .....
6 x 6 = ..... 6 x 10 = .....
6 x 1 = 6 6 x 9 = 54
6 x 2 = 12 6 x 8 = 48
6 x 3 = 18 6 x 7 = 42
6 x 4 = 24 0 x 6 = 0
6 x 5 = 30 6 x 0 = 0
6 x 6 = 36 6 x 10 = 60
Tính nhẩm:
6 x 4 =
6 x 1 =
6 x 9 =
6 x 10 =
6 x 6 =
6 x 3 =
6 x 2 =
0 x 6 =
6 x 8 =
6 x 5 =
6 x 7 =
6 x 0 =
6 x 4 =24
6 x 1 =6
6 x 9 =54
6 x 10 =60
6 x 6 =36
6 x 3 =18
6 x 2 =12
0 x 6 =0
6 x 8 =48
6 x 5 =30
6 x 7 =42
6 x 0 =0
Tìm x, biết:
a, 390 – (x – 7) = 169:13
b, (x – 140) : 7 = 3 3 - 2 3 . 3
c, x – 6 : 2 – (48 – 24) : 2 :6 – 3 = 0
d, x + 5.2 – (32+16.3:6 – 15) = 0
a, x = 384
b, x = 161
c, x = 8
d, x = 15
Tìm x, biết:
a) 390 - ( x - 7 ) = 169 : 13
b) x - 6 : 2 - ( 48 - 24 ) : 2 : 6 - 3 = 0
c) ( x - 140 ) : 7 = 3 3 - 2 3 . 3
d) x + 5 . 2 - ( 32 + 16 . 3 : 6 - 15 ) = 0