Dear friend, Here's your answer... This QUESTION can be solved by using splitting the MIDDLETERM, = x² - 3√5x - 20 = x² - 4√5x + √5x - 20 = x ( x - 4√5 ) + √5 ( x - 4√5 ) = ( x - 4√5 ) ( x + √5 ). Hope it helps you!! PLEASE mark my answer as BRAINLIEST !