72 : (3 x x) = 4
Tìm x biết:
a, (x + 72) × 4 = 320
b, (x - 56) × 7 = 749
c, (x + 3) × 4 = 36
d, (x - 5) × 6 = 72
tim x : 72 : ( 3 x X ) = 4
A=(x^2+x+1)^2-3(x^2+x)-7
B=(x+1).(x+2).(x+3).(x+4)-24
C=(x-7).(x-5).(x-4).(x-2)-72
\(B=\left(x+1\right)\left(x+2\right)\left(x+3\right)\left(x+4\right)-24\)
\(=\left(x^2+5x+4\right)\left(x^2+5x+6\right)-24\)
\(=\left(x^2+5x\right)^2+10\left(x^2+5x\right)\)
\(=\left(x^2+5x\right)\left(x^2+5x+10\right)\)
\(=x\left(x+5\right)\left(x^2+5x+10\right)\)
tính thuận tiện
2/5 + 3/7 + 3/5 + 4/7
2/3 x 4/9 + 2/3 x 5/9
a. 2/5 + 3/7 + 3/5 + 4/7
= (2/5 + 3/5) + (3/7 + 4/7)
= 1 + 1 = 2
b. 2/3 x 4/9 + 2/3 x 5/9
= 2/3 x (4/9 + 5/9)
= 2/3 x 1 = 2/3
Bài 3 Tính nhanh
a, 35 x 34 + 35 x 38 + 65 x 72 + 65 x 72
b, 3 x 25 x 8 + 4 x 37 x 6 + 2 x 38 x12
Các bạn nhớ trình bày giúp mình nhé *.*
a)=35x(34+38)+72x(65+65)
=35x72+72x130
=72x(35+130)
=72x165
=11880
tìm x :
a) 504 : ( 16 - 3 x X ) = 72 d) 272 - (4 x X + 15) = 45
`a, 504 : (16-3x)=72`
`<=> 16-3x=7`
`<=>3x=9`
`<=>x=3`
`b,272-(4x+15)=45`
`<=>4x+15=227`
`<=>4x=212`
`<=>x=53`
a: =>16-3x=504:72=7
=>3x=9
=>x=3
b: =>4x+15=272-45=227
=>4x=212
=>x=53
a) 504 : (16 - 3\(\times\)x) = 72
=> 16 - 3\(\times\)x = 7
=> 3\(\times\)x = 9
=> x = 3
d) 272 - (4\(\times\)x + 15) = 45
=> 4\(\times\)x + 15 = 227
=> 4\(\times\)x = 212
=> x = 53
Tìm x, biết:
a) x = 1 4 + 4 7
b) x − 1 = 7 2 + − 4 − 3
a) x = 1 4 + 4 7 ⇔ x = 1.7 + 4.4 28 = 23 28 ⇔ x = − 23 28 x = 23 28
b) x − 1 = 7 2 + − 4 − 3 ⇔ x − 1 = 29 6 ⇔ x − 1 = 29 6 x − 1 = − 29 6 ⇔ x = 35 6 x = − 23 6
72 + 36 x2 + 24 x 3 + 18 x 4 + 12 x 6 + 168
72 + 36 x 2 + 24 x 3 + 18 x 4 + 12 x 6 + 168
= 72 + 72 + 72 + 72 + 72 + 168
= 72 x 5 + 168
= 360 + 168
= 528
a/ 71- (33 +x) =26
b/ 4(x-3) =72 -110
c/ 32. (x+4) -52=5.22
mình cần gấp
a, 71-(33+x)=26
33+x=71-26
33+x=45
x=45-33
x=12
Vậy x=12
\(71-\left(33+x\right)=26\\ \left(33+x\right)=71-26\\ \left(33+x\right)=45\\ x=45-33\\ x=12\)
a, 71-(33+x)=26
33+x=71-26
33+x=45
x=45-33
x=12
Vậy x=12
b.