Please help! I don't know this question.

The isosceles triangle has two sides of equal length, a, that sre longer than the length of the base ,b. the equation 2a+b=15.7 can be used to find the sides length. if one of the longer sides is 6.3 centimeters what is the length of the base

The verbal translation for the difference of m and 7 increased by 15

Find the midpoint m of z1=(8+5i) and z2=(12+3i)