tìm x
2 nhân x -138 = 72
Tìm số tự nhiên x, biết 3x – 138 = 72.
A: 70
B:22
C: 630
D: 198
Tìm số tự nhiên x, biết 3x – 138 = 72. Giải thích
A:70
B:22
C:630
D:198
3x-138=72
3x= 72+138
3x= 210
x=70
chúc bạn học tốt nè
Bài 1: Tìm x là STN biết:
a) 4(x - 3) = 72 - 20220
b) 123 - 5 x (x + 4) = 38
c) 2x - 138 = 23.32
Mong giúp đỡ ạ!!!
a: =>4(x-3)=49-1=48
=>x-3=12
=>x=15
b: =>123-5(x+4)=38
=>5(x+4)=123-38=85
=>x+4=17
=>x=13
c: =>2x-138=9*8=72
=>2x=72+138=210
=>x=105
1, Tìm x biết :
a, 2 * x - 138 = 8 * 9
b, { ( 6 * x - 72 ) : 2 - 84 ) } * 28 = 5628
c, 420 + 65 * 4 = ( x + 175 ) : 5 + 30
a)\(2.x-138=8.9\)
\(2.x-138=72\)
\(2.x=72+138\)
\(2.x=210\)
\(x=210\div2\)
\(x=105\)
b)\(\left\{\left(6x-72\right)\div2-84\right\}.28=5628\)
\(\left(6x-72\right)\div2-84=201\)
\(\left(6x-72\right)\div2=285\)
\(6x-72=570\)
\(6x=642\)
\(x=107\)
c)\(420+65.4=\left(x+175\right)\div5+30\)
\(420+260=\left(x+175\right)\div5+30\)
\(680=\left(x+175\right)\div5+30\)
\(650=\left(x+175\right)\div5\)
\(3250=x+175\)
\(3075=x\)
a) 2 * x - 138 = 72
2 * x = 72 + 138
x = 210 \ 2
x = 105
Mk thay x=y nha!!!
a)2xy-138=8x9
2xy-138=72
2xy=72+138
2xy=210
y=210:2
y=105
b){(6xy-72):2-84)}x28=5628
{(6xy-72):2-84)}x28=5628
{(6xy-72):2-84=201
{(6xy-72):2=285
(6xy-72)=570
6y=570+72
6y=642
=>y=107
c)420+65x4=(y+175):5+30
680=(y+175):5+30
650=(y+175):5
3250=y+175
y=3250-175
y=3075
2.x-138=72
2 . x - 138 = 72
2 . x = 72 + 138
2 . x = 210
x = 210 : 2
x = 105
2x-138=72
=> 2x = 72+138
2x = 200
x = 200/2
=100
72-x=50
2x-138=72
5.3x = 135
\(72-x=50\\ \Rightarrow x=22\)
\(2x-138=72\\ \Rightarrow2x=210\\ \Rightarrow x=105\)
\(5.3^x=135\\ \Rightarrow3^x=27\\ \Rightarrow3^x=3^3\\ \Rightarrow x=3\)
72−x=50⇒x=2272−x=50⇒x=22
2x−138=72⇒2x=210⇒x=1052x−138=72⇒2x=210⇒x=105
5.3x=135⇒3x=27⇒3x=33⇒x=3
Phân tích đa thức thành nhân tử : 4(x2 + 15x + 50)(x2 + 18x + 72) – 3x2
\(4\left(x^2+15x+50\right)\left(x^2+18x+72\right)-3x^2\\ =4\left(x+5\right)\left(x+10\right)\left(x+6\right)\left(x+12\right)-3x^2\\ =4\left(x^2+16x+60\right)\left(x^2+17x+60\right)-3x^2\)
Đặt \(x^2+16x+60=a\)
\(=4a\left(a+x\right)-3x^2\\ =4a^2+4ax-3x^2\\ =\left(2a-x\right)\left(2a+3x\right)\\ =\left[2\left(x^2+16x+60\right)-x\right]\left[2\left(x^2+16x+60\right)+3x\right]\\ =\left(2x^2+31x+120\right)\left(2x^2+35x+120\right)\)
(x2+15x+50)(x2+18x+72)−3x2=4(x+5)(x+10)(x+6)(x+12)−3x2=4(x2+16x+60)(x2+17x+60)−3x24(�2+15�+50)(�2+18�+72)−3�2=4(�+5)(�+10)(�+6)(�+12)−3�2=4(�2+16�+60)(�2+17�+60)−3�2
Đặt x2+16x+60=a�2+16�+60=�
=4a(a+x)−3x2=4a2+4ax−3x2=(2a−x)(2a+3x)=[2(x2+16x+60)−x][2(x2+16x+60)+3x]=(2x2+31x+120)(2x2+35x+120)
12.( x - 1 ) : 3 = 35
2 . x - 138 =72
310 - ( 118 - x ) 217
a, => 12. ( x - 1 ) = 35 . 3
=> 12. ( x - 1 ) = 105
=> x - 1 = 105 : 12
=> x - 1 = 8,75
=> x = 8,75 + 1
=> x = 9,75
\(a,12.\left(x-1\right):3=35\)
\(12.\left(x-1\right)=35.3\)
\(12.\left(x-1\right)=105\)
\(x-1=105:12\)
\(x-1=\frac{35}{4}\)
\(x=\frac{35}{4}+1\)
\(x=\frac{39}{4}\)
\(b,2.x-138=72\)
\(2.x=72+138\)
\(2.x=210\)
\(x=210:2\)
\(=105\)
\(c,310-\left(118-x\right)=217\)
\(118-x=310-217\)
\(118-x=93\)
\(x=118-93\)
\(x=25\)
Học tốt
b, => 2x = 72 + 138
=> 2x = 210
=> x = 210 : 2
=> x = 105
tìm x biết :
918: 9 - . ( 72 - 36 x2 : 4 -12 ) =50
dấu chấm là x nha