Math help (radical expressions) ???
2 answers:
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-5x-12>6x-4
To Solve the inequality we need to get x alone
-5x-12>6x-4
first we remove -12, for that we add 12 on both sides
-5x-12+12>6x-4+12
-5x > 6x +8
Now subtract 6x from both sides
-5x -6x> 6x-6x +8
-11x > 8
Divide by -11. when we divide by -11 we flip the inequality . so > becomes <
We need to give the answer in interval notation.
x is less than -8/11 so x value starts from -8/1 and goes to -infinity(left)
So interval notation is (-∞, )
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.