Can someone please explain how to do this problem:

n(x)=4x+15; n(x)=7

Thanks

The equation y=mx+b is the slope-intercept form of the equation of a line. what is the equation solved for b? y-m=b y-mx=b y/mx=b y/m-x=b

Consider a graph for the equation y= -3x+4. what is the y intercept? a) 4 b) -4 c) 3 d) -3

Ameteorologist is studying the monthly rainfall in a section of the brazilian rainforest. she recorded the monthly rainfall, in inches, for last year. they were: 10.4, 10.3, 11.7, 11.1, 8.0, 4.4, 2.6, 1.8, 2.5, 4.4, 7.3, 9.5 fill in the missing values in the formula. what is the variance?