Answer:
-6
Step-by-step explanation:
We know that since Ax + By = 3 passes through (-7, 2), then if we plug -7 in for x and 2 in for y, the equation is satisfied. So, let's do that:
Ax + By = 3
A * (-7) + B * 2 = 3
-7A + 2B = 3
We also know that this line is parallel to x + 3y = -5, which means their slopes are the same. Let's solve for y in the second equation:
x + 3y = -5
3y = -x - 5
y = (-1/3)x - (5/3)
So, the slope of this line is -1/3, which means the slope of Ax + By = 3 is also -1/3. Let's solve for y in the first equation:
Ax + By = 3
By = -Ax + 3
y = (-A/B)x + 3/B
This means that -A/B = -1/3. So, we have a relationship between A and B:
-A/B = -1/3
A/B = 1/3
B = 3A
Plug 3A in for B into the equation we had where -7A + 2B = 3:
-7A + 2B = 3
-7A + 2 * 3A = 3
-7A + 6A = 3
-A = 3
A = -3
Use this to solve for B:
B = 3A
B = 3 * (-3) = -9
So, B = -9 and A = -3. Then B - A is:
B - A = -9 - (-3) = -9 + 3 = -6
The answer is -6.
<em>~ an aesthetics lover</em>
Answer:
C
Step-by-step explanation:
Y = -(1/2)(x-2)² +8
Re write it in standard form:
(y-8) = -1/2(x-2)² ↔ (y-k) = a(x-h)²
This parabola open downward (a = -1/2 <0), with a maximum shown in vertex
The vertex is (h , k) → Vertex(2 , 8)
focus(h, k +c )
a = 1/4c → -1/2 = 1/4c → c = -1/2, hence focus(2, 8-1/2) →focus(2,15/2)
Latus rectum: y-value = 15/2
Replace in the equation y with 15/2→→15/2 = -1/2(x-2)² + 8
Or -1/2(x-2)² +8 -15/2 = 0
Solving this quadratic equation gives x' = 3 and x" = 2, then
Latus rectum = 5
Step-by-step explanation:
- (-2)4 = -8
- -8 +(-10)= -18
- -18 divide by -5= 18/5
Points (1, 7) and (-3, 2)
Slope for a line between (x₁, y₁) and (x₂, y₂) , m = (y₂ -y₁) / (x₂- x₁)
The slope for the line joining the two points = (2 - 7) / (-3 - 1) = -5/-4
Slope = 5/4
Hence the perpendicular bisector would have a slope of -1/(5/4) = -4/5
By condition of perpendicularity
For points (1, 7) and (-3, 2),
Formula for midpoints for (x₁, y₁) and (x₂, y₂) is ((x₁ +x₂)/2 , (y₁+ y₂)/2)
Midpoint for (1, 7) and (-3, 2) = ((1+ -3)/2 , (7+2)/2) = (-2/2, 9/2)
= (-1, 9/2)
Since the slope of perpendicular bisector is -4/5 and passes through the midpoint (-1, 9/2)
Equation y - y₁ = m (x - x₁)
y - 9/2 = (-4/5) (x - -1)
y - 9/2 = (-4/5)(x + 1)
5(y - 9/2) = -4(x + 1)
5y - 45/2 = -4x - 4
5y = -4x - 4 + 45/2
5y + 4x = 45/2 - 4
5y + 4x = 22 1/2 - 4 = 18 1/2
5y + 4x = 37/2
10y + 8x = 37
The equation of the line to perpendicular bisector is 10y + 8x = 37
