3-3 0
——- = —— = zero
-9-9. -18
This is an algebra problem pretending to be geometry. The perimeter is the sum of the sides. Geometry done.
3x + (2x + 1) + 2(x + 4) = 37
7x + 9 = 37
7x = 28
x = 4
Choice B
13(y - 10) = -4
13y - 130 = -4
13y - 130 + 130 = -4 + 130
13y = 126
13y/13 = 126/13
y = 126/13
Question 14, Part (i)
Focus on quadrilateral ABCD. The interior angles add to 360 (this is true for any quadrilateral), so,
A+B+C+D = 360
A+90+C+90 = 360
A+C+180 = 360
A+C = 360-180
A+C = 180
Since angles A and C add to 180, this shows they are supplementary. This is the same as saying angles 2 and 3 are supplementary.
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Question 14, Part (ii)
Let
x = measure of angle 1
y = measure of angle 2
z = measure of angle 3
Back in part (i) above, we showed that y + z = 180
Note that angles 1 and 2 are adjacent to form a straight line, so we can say
x+y = 180
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We have the two equations x+y = 180 and y+z = 180 to form this system of equations
Which is really the same as this system
The 0s help align the y terms up. Subtracting straight down leads to the equation x-z = 0 and we can solve to get x = z. Therefore showing that angle 1 and angle 3 are congruent. We could also use the substitution rule to end up with x = z as well.
Looking at this, the unit of 1 length is equal to 2.5 units of width. To find 6 units of length, you just multiply 6 by 2.5. Getting this gives us 15. So your answer is C.