Bonjour
a) 5+1.5t=3+2.5t
⇔1.5t-2.5t=3-5
⇔-1t=-2
⇔t=-2/-1
⇔t=2
b)3y-3.5=9y-3.5
⇔3y-9y=-3.5+3.5
⇔-6y=0
⇔y=0
c)2.5z+5=-2.5z-5
⇔2.5z-2.5z=-5-5
⇔0z=-10
d)0.5t+1=2t+1.5
⇔0.5t-2t=1.5-1
⇔-1.5t=0.5
⇔t=0.5/-1.5
⇔t=-1/3
e)8y=y+1.5
⇔8y-y=1.5
⇔7y=1.5
⇔y=1.5/7
f)7.8i-8=1.3i+2
⇔7.8i-1.3i=2+8
⇔6.5i=10
⇔i=10/6.5
