Question

What is f(x)=7x^2+42x written in veryex form

Answer 1

`The\ vertex\ form\ of\ f(x)=ax^2+bx+c\\\\f(x)=a(x-p)^2+q\ where\ p=(-b)/(2a)\ and\ q=(-(b^2-4ac))/(4a)=f(p)\\--------------------------\\\\f(x)=7x^2+42x\\\\a=7;\ b=42;\ c=0\\\\p=(-42)/(2\cdot7)=-(42)/(14)=-3\\\\q=f(-3)=7\cdot(-3)^2+42\cdot(-3)=7\cdot9-126=63-126=-63\\\\\boxed{f(x)=7(x+3)^2-63}`

Answer 2

Hello,

f(x)=7x²+42x=7(x²+2*3x+9)-63=7(x+3)²-63.