Answer:
Each chord is cut into two segments at the point of where they intersect. One chord is cut into two line segments A and B. The other into the segments C and D. This theorem states that A×B is always equal to C×D no matter where the chords are.
Step-by-step explanation:
We have to get one positive 7y so,
4x-7y=5
9x-7y=-15
multiply anyone of the equation by -1. I choose the first one so,
4x+7y=-5
9x-7y=-15
we can now cancel the y's so the equation will be left with
-4x=-5
9x=-15
add the equations
5x=-20
divide by 5 n u get
x=-4
now plug in the x value in any one of the
equations
I choose the first one so,
4(-4)-7y=5
-16-7y=5
add 16 to both sides
-7y=21
divide by -7
y=-3.
finally check.
Look carefully at the first pair: (−3, 9), (−3, −5) Note that x does not change, tho' y does. This is how we recognize a vertical line (whose slope is undefined). The equation of this vertical line is x = -3.
Looking at the second pair: from (3,4) to (5,6), x increases by 2 and y by 2; thus, the slope is m = rise/run = 2/2 = 1.
Third pair: as was the case with the first pair, x does not change here, and thus the equation of this (vertical) line is x=0 (which is the y-axis). The slope is undefined.
Answer:
B
Step-by-step explanation:
Tell me if you need an explanation
We have,

Introduce variable
such that 
The sum
is therefore 
So,
(sadia's age)
(father's age)
Hope this helps :)