Learn how to solve problems step by step online. Expand the expression (5m^2-y^2)^3. The cube of a binomial (difference) is equal to the cube of the first term, minus three times the square of the first by the second, plus three times the first by the square of the second, minus the cube of the second term. In other words: (a-b)^3=a^3-3a^2b+3ab^2-b^3 = (5m^2)^3+3(5m^2)^2(-y^2)+3(5m^2)(-y^2)^2+(-y^2)^3 =. Simplify \left(-y^2\right)^2. Simplify \left(y^2\right)^2 using the power of a power property: \left(a^m\right)^n=a^{m\cdot n}. In the expression, m equals 2 and n equals 2. Simplify \left(-y^2\right)^3 by taking the minus sign (-) out of the power.

Expand the expression (5m^2-y^2)^3