Answer:
1.In △XYZ, XY=XZ.
We have to Find the length of XY of △XYZ if XY=2a, YZ=3a+1, and XZ=5a−12.
Now, X Y=X Z [given]
→2 a= 5 a-12
Bringing like terms on same side
→2 a-5 a=-12
→-3 a=-12
→a=(-12)÷(-3)
a=4 is correct answer among all the options.
2.In △ABC, m∠A=(4x+7)° and m∠B=(5x−3)°.
What is m∠B?
Ans: as ∠ C not given we can't find ∠B.