B3
\(a.\left(x-25\right)-175=0\\ x-\left(25+175\right)=0\\ x-200=0\\ x=200\\ b.315+\left(135-x\right)=450\\ \left(315+135\right)-x=450\\ 500-x=450\\ x=500-450\\ x=50\\ c.346+\left(210-x\right)=556\\ \left(346+210\right)-x=556\\ 556-x=556\\ x=0\\ d.x\cdot14-x\cdot2=120\\ x\cdot12=120\\ x=120:12\\ x=10\\ e,x\cdot5+10\cdot9=990\\ x\cdot5+90=990\\ x\cdot5=990-90\\ x\cdot5=900\\ x=900:5\\ x=180\\ f.x\cdot34-x\cdot14=200\\ x\cdot20=200\\ x=200:20\\ x=10\)
Bài 2
a | 328 | 141 | 15 | 982 | 1005 |
b | 32 | 12 | 4 | 47 | 40 |
q | 10 | 11 | 3 | 20 | 25 |
r | 8 | 9 | 3 | 42 | 5 |
Cột cuối có thể có b = 39, r = 30