First you subtract 8x to both sides so you get
2y=-8x+ 70
then you divide 2 with everything to get y by itself
-4x+35=y
If the numbering of the angles is similar to this:
1 | 2
-----
3 | 4
5 | 6
----
7 | 8
Then none of the the choices are necessarily true.
The equations would have been:
1 = 4 = 5 = 8
2 = 3 = 6 = 7
3 + 5 = 4 + 6 = 180
The third one just like the previous question
Answer:
since the lengths are consecutive odd numbers and the perimeter of the triangle is 51cms. Let x be the unknown length.
so 3x=51 ; x=17 . now the sides can be 15cms, 17cms, 19cms.
check Add them up it is 51cms which is the perimeter and the consecutive odd numbers
Cross multiply the expression so that we can get
(1+sinx)(1-sinx) = cos^2 x
1 - sin^2 x = cos^2 x
cos^2 x + sin^2 x = 1
since
cos^2 x + sin^2 x = 1
therefore
1 = 1
the two expressions are identical in a trigonometric sense
