Digital SAT Math Practice Questions and Answers

When does the sign change in an inequality?When multiplying or dividing both sides with a negative number Number of solutionsone solution: x/y = a no solution: a = b infinite solutions: a = a What is slope intercept form? Identify what each variable means.y= mx + b m = slope (or "rate") b = y-int What is the formula for slope?y2-y1 / x2-x1 or rise/run Parallel Lines-same slope (different y-intercept) - do not intersect (unless they overlap completely) Perpendicular Lines- form 90 degree angles w/ each other - slopes are negative inverse of each other (swap numerator and denominator & change the sign) Two ways to solve for systems of equations:- substitution - elimination How many solutions does each system have?diff slopes = one solution same slopes, diff b-values = no solutions same slopes, same b-values = infinite