1.6 x 10^3 and 2.9 x 10^3 expressed in scientific notation

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula, equation, to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

Sorry guys but as you have a small brain

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?