Question

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 x + 3y = -5. Pls help ASAP btw, the answer isn’t -12/19 or 12/19

Answer 1

Answer:

$B - A = -6$

Step-by-step explanation:

Given

Point: (-7,2)

x + 3y = -5

Required

Find B- - A in Ax + By = 3

To start with; we need to calculate the slope of x + 3y = -5

$x + 3y = -5$

Subtract x from both sides

$x - x + 3y = -5 - x$

$3y = -5 - x$

Divide both sides by 3

$\frac{3y}{3} = -\frac{5}{3} - \frac{x}{3}$

$y = -\frac{5}{3} - \frac{x}{3}$

The slope of the line is the coefficient of x

Slope = $- \frac{1}{3}$

The question says line Ax + By = 3 is parallel to line x + 3y = -5; This means that they have the same slope of $- \frac{1}{3}$

Having calculated the slope, next is to calculate the equation of the line using the following formula;

$m = \frac{y - y_1}{x - x_1}$

Where m is the slope; m = $- \frac{1}{3}$; $(x_1, y_1) = (-7,2)$

Substitute these values in the formula above; the formula becomes

$-\frac{1}{3} = \frac{y - 2}{x - -7}$

$-\frac{1}{3} = \frac{y - 2}{x +7}$

Cross Multiply

$-1(x+7) = 3(y-2)$

Open brackets

$-x - 7 = 3y - 6$

Add x to both sides

$x - x - 7 = 3y - 6 + x$

$-7 = 3y - 6 +x$

Add 6 to both sides

$-7 + 6 = 3y -6 + 6 + x$

$-1 = 3y + x$

Multipby both sides by -3

$-3(-1) = -3(3y + x)$

$3 = -9y - 3x$

$-9y - 3x = 3$

$-3x - 9y = 3$

Comparing the above to Ax + By = 3

$Ax = -3x\\A = -3$

$By = -9y\\B = -9$

$B - A = -9 - (-3)$

$B - A = -9 + 3$

$B - A = -6$