So firstly, we have to find the y-intercept of the first equation given to us; x + 2y = 10. The easiest method of doing this is to put this equation into slope-intercept form, which is y = mx + b (m = slope, b = y-intercept.)
First step is to subtract x on both sides of that equation: 2y = -x + 10
Next, divide 2 on both sides of the equation, and your slope-intercept form is: y = -1/2x + 5.
Looking at that equation, it appears that our y-intercept is (0,5).
Next, the slope formula is
. For this, I'll be using points (9,7) and (0,5).
![(7-5)/(9-0)=(2)/(9)](https://img.qammunity.org/2019/formulas/mathematics/high-school/g2vroxy6sd4jgbvdk82rqwit5z85g8v8dm.png)
In short, the slope is 2/9, or B.