Math reasoning exercise set 8

m³+m² = 80

What is the value of m?

m³+m² = 80.  A cube of a number + square of the same number = 80. Write all the squares and cubes. Look at a suitable pair that adds to 80

m³+m² = 64+16.  m³+m² = 4³+4²  m =4

Another Sum

m²-m³=80…(I)

What is the value of m?

m²–m³ = 80        m²–m³ = 64+16          m² –m³= 4³+4²

m²(1-m) = 4²(4+1)      Lets take first term     m² = 4²

m can be +4 or -4

Substitute in equation (1)

Only m=-4 satisfies