Question 1089997
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The points (10,9) and (a,1) can be thought of as (x1,y1) and (x2,y2) respectively.


So,
(x1,y1) = (10,9)
(x2,y2) = (a,1)
which means
x1 = 10, y1 = 9
x2 = a, y2 = 1


The given slope is m = 8. Plug this m value and the x,y values discussed above, into the slope formula. Then solve for 'a'


{{{m = (y[2]-y[1])/(x[2]-x[1])}}}


{{{8 = (1-9)/(a-10)}}}


{{{8 = -8/(a-10)}}}


{{{8(a-10) = (-8/(a-10))*(a-10)}}} Multiply both sides by (a-10)


{{{8(a-10) = -8}}}


{{{8a-80 = -8}}} Distribute


{{{8a-80+80 = -8+80}}} Add 80 to both sides


{{{8a = 72}}}


{{{8a/8 = 72/8}}} Divide both sides by 8 to isolate 'a'


{{{a = 9}}}


Answer: <font color=red>a = 9</font>
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