A: Đặt P(x)=0
=>3x-5=0
hay x=5/3
b: Đặt Q(x)=0
=>-2x+6=0
hay x=3
c: Đặt M(y)=0
=>1/2y-3=0
hay y=6
d: Đặt A(x)=0
=>12-3/4x=0
=>3/4x=12
hay x=16
Bài 7
a)cho P(x) = 0
\(=>3x-5=0\Leftrightarrow3x=5\Leftrightarrow x=\dfrac{5}{3}\)
b) cho Q(x) = 0
\(=>6-2x=0\Leftrightarrow2x=6\Leftrightarrow x=3\)
c)cho M(y) = 0
\(=>\dfrac{1}{2}y-3=0\Leftrightarrow\cdot\dfrac{1}{2}y=3\Leftrightarrow y=6\)
d)cho A(x) = 0
\(=>\dfrac{-3}{4}x+12=0=>-\dfrac{3}{4}x=-12=>x=16\)
e)cho B(y) = 0
=>\(2y+15=0=>2y=-15=>y=-\dfrac{15}{2}\)
f) cho C(t) = 0
=>\(2-5t=0=>5t=2=>t=\dfrac{2}{5}\)
a) \(P\left(x\right)=3x-5\)
\(3x-5=0\)
\(\)\(3x=5\)
\(x=5:3\)
\(x=\dfrac{5}{3}\)
Vậy.......
b) \(Q\left(x\right)=6-2x\)
\(6-2x=0\)
\(2x=6\)
\(x=3\)
Vậy....
c) \(M\left(y\right)=\dfrac{1}{2}y-3\)
\(\dfrac{1}{2}y-3=0\)
\(\dfrac{1}{2}y=3\)
\(y=6\)
Vậy....
d) \(A\left(x\right)=\dfrac{-3}{4}x+12\)
\(\dfrac{-3}{4}x+12=0\)
\(\dfrac{-3}{4}x=-12\)
\(x=16\)
Vậy...
e) \(B\left(y\right)=2y+18\)
\(2y+18=0\)
\(2y=-18\)
\(y=-9\)
Vậy...
f) \(C\left(t\right)=2-5t\)
\(2-5t=0\)
\(5t=2\)
\(x=\dfrac{2}{5}\)
Vậy...
