Question

plz someone help me to do this no.​

Answer 1

Step-by-step explanation:

Given ,

$p + q = 5$

So we know that

$( {a + b})^{3} = {a}^{3} + {b}^{3} + 3ab(a + b)$

So cubing both side the given equation

$({p + q})^{3} = {p}^{3} + {q}^{3} + 3pq(p + q) \\ \implies {5}^{3} = {p}^{3} + {q}^{3} + 3pq \times 5 \\ \implies125 = {p}^{3} + {q}^{3} + 15pq \\ \implies {p}^{3} + {q}^{3} + 15pq = 125$

Hence prove

Answer 2

Given:

p + q = 5

To Prove:

p³ + q³ + 15pq = 125

Solution:

$p \: + q \: = 5$

[cubing both side]

${(p + q)}^{3} = {5}^{3} \\ \\ {p}^{3} + {q}^{3} + 3pq( p+ q) = 125 \\ \\ {p}^{3 } + {q}^{3} + 3pq(5) = 125 \\ \\ {p}^{3} + {q}^{3} + 15pq = 125$

Hence Proved .