Answer:
(x, y) = (1, -1)
Step-by-step explanation:
We'll write these equations in general form, then solve using the cross-multiplication method.
43x +67y +24 = 0
67x +43y -24 = 0
∆1 = (43)(43) -(67)(67) = -2640
∆2 = (67)(-24) -(43)(24) = -2640
∆3 = (24)(67) -(-24)(43) = 2640
These go into the relations ...
1/∆1 = x/∆2 = y/∆3
x = ∆2/∆1 = -2640/-2640 = 1
y = ∆3/∆1 = 2640/-2640 = -1
The solution is (x, y) = (1, -1).
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<em>Additional comment</em>
The cross multiplication method isn't taught everywhere. The attachment explains a bit about it. Our final relationship changes the order of the fractions to 1, x, y from x, y, 1. That way, we can use the equation coefficients in their original general-form order. (The fourth column in the 2×4 array of coefficients is a repeat of the first column.)
Answer:
Option A is the correct answer.
Explanation:
The given pyramid has 3 lateral triangular side as shown below.
Base of triangle = 12 unit
We need to find perpendicular.
By Pythagoras theorem we have
Perpendicular² = 10²-6²
Perpendicular = 8 unit
So area of 1 lateral triangle = 1/2 x Base x Perpendicular.
= 1/2 x 12 x 8 = 48 unit²
Area of lateral side = 3 x 48 = 144 unit²
Option A is the correct answer.
2, 5, 8, 11, 14 is an arithmetic sequence