Let's solve for c.
x2+18x+c=25+c
Step 1: Add -c to both sides.
x2+c+18x+−c=c+25+−c
x2+18x=25
Step 2: Add -x^2 to both sides.
x2+18x+−x2=25+−x2
18x=−x2+25
Step 3: Add -18x to both sides.
18x+−18x=−x2+25+−18x
0=−x2−18x+25
Step 4: Divide both sides by 0.
00=−x2−18x+250
c=−x2−18x+250
Answer:
c=−x2−18x+250