$\text { Đáp án: }$
$\text { a) 8,75 × y + 1,25 × y }$
$\text { => y × (8,75 + 1,25) = 0 }$
$\text { => y × 10 = 0 }$
$\text { => y = 0 : 10 }$
$\text { => y = 0. }$
$\text { b) 175,5 – [y + 120] = 6,75 + 3,5 }$
$\text { => 175,5 – [y + 120] = 10,25 }$
$\text { => y + 120 = 175,5 – 10,25 }$
$\text { => y + 120 = 165,25 }$
$\text { => y = 165,25 – 120 }$
$\text { => y = 45,25. }$