Prove algebraically that the sum of the squares of two consecutive multiples of 5 is not a multiple of 10.

First let’s break this statement down. At the core of this sentence are two consecutive multiples of 5. How can we represent these using algebra? Let’s use 5a where “a” is an integer. A consecutive multiple of 5 would then be 5(a + 1). Use an example for “a” to understand this.Then, the SUM of the SQUARES refers precisely to the following:(5a)^2 + (5(a+1))^2which when expanded, becomes50a^2 + 10a + 25 Under evaluation, the first 2 terms will always be multiples of 10, but adding 25 stops the entire expression from being a multiple of 10.

DS
Answered by Daniel S. Maths tutor

5030 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

How do you differentiate using the chain rule?


Imagine a sector of a circle called AOB. With center O and radius rcm. The angle AOB is R in radians. The area of the sector is 11cm². Given the perimeter of the sector is 4 time the length of the arc AB. Find r.


The line L1 has vector equation,  L1 = (  6, 1 ,-1  ) + λ ( 2, 1, 0). The line L2 passes through the points (2, 3, −1) and (4, −1, 1). i) find vector equation of L2 ii)show L2 and L1 are perpendicular.


Given that x = cot y, show that dy/dx = -1/(1+x^2)


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning