Respuesta :

[tex]f(a) = -4a +6a^3 - 15 -4a^2 \\\\\text{By the remainder theorem,}\\\\f\left(\dfrac 53 \right) = -4\left(\dfrac 53 \right) + 6 \left( \dfrac 53 \right)^3 - 15 - 4 \left(\dfrac 53 \right)^2 = -5\\\\\\ \text{Hence}~-5~ \text{is the remainder when f(a) is divided by}~ 3a -5[/tex]

[tex]\\ \sf\longmapsto 3a-5=0[/tex]

[tex]\\ \sf\longmapsto 3a=5[/tex]

[tex]\\ \sf\longmapsto a=\dfrac{5}{3}[/tex]

Using remainder theorem

[tex]\\ \sf\longmapsto f(a)=-4a+6a^2-4a^2-15[/tex]

[tex]\\ \sf\longmapsto f\left(\dfrac{5}{3}\right)[/tex]

[tex]\\ \sf\longmapsto -4(5/3)+2a^2-15[/tex]

[tex]\\ \sf\longmapsto -20/3+2(5/3)^2-15[/tex]

[tex]\\ \sf\longmapsto -20/3+2(25/9)-15[/tex]

[tex]\\ \sf\longmapsto -20/3+50/9-15[/tex]

[tex]\\ \sf\longmapsto (-60+50)/9-15[/tex]

[tex]\\ \sf\longmapsto -10/9-15[/tex]

[tex]\\ \sf\longmapsto -10-135/9[/tex]

[tex]\\ \sf\longmapsto -145/9[/tex]

[tex]\\ \sf\longmapsto 16\dfrac{-5}{9}[/tex]

Remainder=-5