If the slope is 7, and the given coordinates are (x , 8) and (4 , 1), how do you find x?

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Answer 1 · 2015-06-11T21:33:43

There's a formula for slope:

$(Deltay)/(Deltax) = (y_2 - y_1)/(x_2 - x_1) = "slope"$

$"slope" = 7 = (1 - 8)/(4-x_1) = (1 - 8)/(4-x)$

$7(4-x) = -7$

$28 - 7x = -7$

$35 = 7x$

$x = 5$

And for the big picture:

$y = mx+b$

$1 = 7(4) + b$
$b = -27$

$y = 7x - 27$ therefore has the points $(5,8)$ and $(4,1)$ . You can find them here:

graph{7x -27 [-5.67, 14.33, -1.34, 8.66]}