x:3=678-561

x:3=117

x=117x3

x=351

678-x*3=561

       x*3=678-561

        x*3=117

        x   =117:3

        x   =39

Thì x:3=678-516
      x:3=162
      x   =162 :3
      x   =54

=561/704*(39/47+8/47)

=561/704*47/47

=561/704*1

=561/704

\(\frac{561}{704}.\frac{39}{47}+\frac{561}{704}.\frac{8}{47}\)

\(=\frac{561}{704}.\left(\frac{39}{47}+\frac{8}{47}\right)\)

\(=\frac{561}{704}.1\)

\(=\frac{51}{64}\)

564/704.39/47+561/704.8/47

=564/704.(39/47+8/47)

=564/704.1

=141/176

x = - 251 tk mk nha bạn !!

x+561=908-598

x+561=310

x=310-561

x=-251

k mk nhe

x+561=310

x=310-561

x=-251

tk minh nha

Chọn C

c

\(a.\left[x\cdot\left(x+1\right)\right]:2=136\\ x\cdot\left(x+1\right)=136\cdot2\\ x\cdot\left(x+1\right)=2\cdot2\cdot2\cdot17\cdot2\\ x\cdot\left(x+1\right)=\left(2\cdot2\cdot2\cdot2\right)\cdot17\\ x\cdot\left(x+1\right)=16\cdot17\\ =>x=16\\ b.\left[x\cdot\left(x+1\right)\right]:2=300\\ x\cdot\left(x+1\right)=3\cdot2\cdot2\cdot5\cdot5\cdot2\\ x\cdot\left(x+1\right)=\left(3\cdot2\cdot2\cdot2\right)\cdot\left(5\cdot5\right)\\ x\cdot\left(x+1\right)=24\cdot25\\ =>x=24\\ c.\left[x\cdot\left(x+1\right)\right]:2=561\\ x\cdot\left(x+1\right)=2\cdot3\cdot11\cdot17\\ x\cdot\left(x+1\right)=\left(17\cdot2\right)\cdot\left(3\cdot11\right)\\ x\cdot\left(x+1\right)=34\cdot33\\ =>x=33\)

83 x 16 + 8 x 32 + 16 = 83 x 16 + 16 x 16 + 1 x 16 = 16 x (83+16+1) = 16 x 100 = 1600

1+2+3+.......+x = 561

x(x+1) : 2 = 561

x(x+1) = 561 x 2 = 1122

Mà 1122 = 33 x 34

Vậy x = 33

.

.                                                                                                               .