OpenStudy (anonymous):

4 years ago
OpenStudy (anonymous):

4 years ago
OpenStudy (anonymous):

Slope intercept form of a linear equation is y=ax+b where x and y are coordinates (abscissa and ordinate) and a and b are some constants. So you have to determine these two constants, a and b. 1.The first graph goes through point with coordinates (0,0) and (-4,1). Therefore, if we substitute these values of x and y into an equation y=ax+b, we will get 0=a*0+b and 1=a*(-4)+b This is a system of two linear equations with two variables. From the first equation we get b=0, from the second (considering b=0) a=-1/4. Therefore, the equation is y=(-1/4)x. 2. Graph goes through points (2,1) and (1,-1). Therefore, using the same technique, 1=a*2+b and -1=a*1+b The easiest way to solve this system of equations is to subtract the second equation from the first. Variable b will disappear: (1) - (-1) = (a*2+b) - (a*1+b) Simplifying, 2=a*2+b-a*1-b or 2=a Now, knowing that a=2, substitute it in to first equation in the system to get b: 1=2*2+b or b=-3 Therefore, the equation is y=2x-3 You can use the same method for all other problems. Additional theory can be found on my site UNIZOR.COM. It's free.

4 years ago