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Find the value of B - A if the graph of Ax + By = 3 passes through the point (-7,2), and is parallel to the graph of x + 3y = -5.

Apr 7, 2021

#1
+11856
+3

Find the value of B - A if the graph of Ax + By = 3 passes through the point (-7,2),

and is parallel to the graph of x + 3y = -5.

$$x + 3y = -5\\ y=-\frac{1}{3}x-\frac{5}{3}\\ \color{blue}m=-\frac{1}{3}$$

$$\color{blue}y=m(x-x_p)+y_p\\ y=-\frac{1}{3}(x-(-7))+2\\ y=-\frac{1}{3}x-\frac{7}{3}+\frac{6}{3}\\ \color{blue}y=-\frac{1}{3}x-\frac{1}{3}$$

$$Ax + By = 3\\ \frac{1}{3}x+y=-\frac{1}{3}\ |\ \cdot -9\\ \color{blue}-3x-9y=3\\ A-B=-3-(-9)$$

$$\color{blue}A-B=6$$

Because of the language barrier,

$$\color{blue}B-A =-6$$

!

Apr 7, 2021
edited by asinus  Apr 7, 2021
edited by asinus  Apr 7, 2021
edited by asinus  Apr 7, 2021
edited by asinus  Apr 7, 2021
#2
+46
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You're supposed to actually subtract A from B, not vice versa, but ok