Answer:
p = [tex]\frac{12}{7}[/tex]
Step-by-step explanation:
let the root be α then the other root is 3α
The sum of the roots of a quadratic equation is
α + 3α = - [tex]\frac{b}{a}[/tex] = - [tex]\frac{-8}{7}[/tex] = [tex]\frac{8}{7}[/tex]
Thus 4α = [tex]\frac{8}{7}[/tex] ( divide both sides by 4 )
α = [tex]\frac{2}{7}[/tex]
The product of the roots of a quadratic equation are
α × 3α = [tex]\frac{c}{a}[/tex] = [tex]\frac{p}{7}[/tex], that is
3α² = [tex]\frac{p}{7}[/tex] ← substitute value of α
3 × ([tex]\frac{2}{7}[/tex] )² = [tex]\frac{p}{7}[/tex]
3 × [tex]\frac{4}{49}[/tex] = [tex]\frac{p}{7}[/tex]
[tex]\frac{12}{49}[/tex] = [tex]\frac{p}{7}[/tex] ( cross- multiply )
49p = 84 ( divide both sides by 49 )
p = [tex]\frac{84}{49}[/tex] = [tex]\frac{12}{7}[/tex]
