Please help, quick math, and a short explanation on how you got the answer! Thank you!!

this is an iscoceles triangle.

I know this because 2 of the sides are equal in length

Therefore,

AB=AC

3x-5=-2x+15

x-5=15

x=20

if x=20 then BC=2(20)

BC=40

Step-by-step explanation:

26 is 33.33% of 78

step-by-step explanation:

26 is what percent of 78?

26 is p% of 78

equation: y = p% * x

solving our equation for p

p% = y/x

p% = 26/78

p = 0.3333

convert decimal to percent:

p% = 0.3333 * 100 = 33.33%