Question

Find the value of c such that each expression is a perfect-square trinomial.

Please show steps on all thank you!
1.  x^2-16x+c
2. p^2-14p+c
3. b^2+18b+c
4. n^2-n+c

Answer 1

`(a\pm b)^2=a^2\pm2ab+b^2\\\\1.\ x^2-16x+c=x^2-2x\cdot8+c\to c=8^2=64\\\\x^2-16x+64=x^2-2x\cdot8+8^2=(x-8)^2\\\\\\2.\ p^2-14p+c=p^2-2p\cdot7+c\to c=7^2=49\\\\p^2-14p+49=p^2-2p\cdot7+7^2=(p-7)^2`



`3.\ b^2+18b+c=b^2+2b\cdot9+c\to c=9^2=81\\\\b^2+18b+81=b^2+2b\cdot9+9^2=(b+9)^2\\\\\\4.\ n^2-n+c=n^2-2n\cdot(1)/(2)\to c=((1)/(2))^2=(1)/(4)\\\\n^2-n+(1)/(4)=n^2-2n\cdot(1)/(2)+((1)/(2))^2=(n-(1)/(2))^2`