They gave you the lengths showing each side of the original triangle is congruent to each side of the new triangle. There is no information to show if the triangle was rotated or reflected, so although it is possible that it was, we can't really tell. All we know is the triangles are congruent.
43 6 goes into 25 4 times equaling 24 put the 1 carry down thw 8 6 time 3 is 18 that's 43
Remember you can do anything to an equation as long as you do it to both sides
8-(3+b)=b-9
remember the distributive property
a(b+c)=ab+ac
distribute that invisible -1
-(3+b)=-1(3+b)=-1(3)-1(b)=-3-b
8-3-b=b-9
add like terms
5-b=b-9
add b to both sides
5=2b-9
add 9 to both sides
14=2b
divide both sides by 2
7=b
b=7
