Which term best describes a proof in which you assume the opposite of what you want to prove

Simone claims the initial value and y-intercept are the same thing on a graph. is she correct? if you know that a line has a slope of and a y-intercept of 7, what is the equation for that line in slope-intercept form?

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Find the least common denominator for thesetvo rational expressions. n^2/n^2+4n+4 -3/n^2+7n+10