A mother function is the simplest function of a family of functions.
30,000
the way you can solve this is by removing all numbers in front of the selected number(in this case, 2 should be removed) then change all numbers behind to 0.
Steps
8x−7y=−5
Add 7y to both sides
8x−7y+7y=−5+7y
Simplify
8x=−5+7y
Divide both sides by 8
8x
8 =−
5
8 +
7y
8
Simplify
x=
−5+7y
8
Replace all values of x as 4
f(4)=1/2(4)+5
f(4)=4/2+5
f(4)=2+5
f(4)=7
Hope I helped :)