Exponents and Polynomials Factoring out a constant before factoring a quadratic Factor completely. \[ 5 y^{2}+5 y-100 \]

Step 1 ：The given expression is a quadratic equation: \(5 y^{2}+5 y-100\).

Step 2 ：The first step to factorize this equation is to factor out the common factor, which is 5 in this case: \(5(y^{2}+y-20)\).

Step 3 ：After factoring out the common factor, we can then factorize the quadratic equation: \(5(y - 4)(y + 5)\).

Step 4 ：The factored form of the given expression is \(\boxed{5(y - 4)(y + 5)}\).