If the graph of y=3x^2+2x is vertically stretched by a factor of 9 and horizontally stretched by a factor of 7/2, determine the equation that describes the transformed graph?

1 Answer
Nov 19, 2017

y=12/245x^2+4/35xy=12245x2+435x

Explanation:

Let f(x)=3x^2+2xf(x)=3x2+2x

A vertical stretch of f(x), SF aa would be af(x)af(x) This gives us the first transformation, 5f(x)5f(x)
A horizontal stretch, SF bb would be f(1/bx)f(1bx) (the reciprocal of the scale factor).

This gives us f(2/7x)f(27x)
Combining these, we get 5f(2/7x)5f(27x)

Replacing this back into y=f(x)y=f(x), we get:
5y=3(2/7x)^2+2(2/7x)5y=3(27x)2+2(27x)
5y=12/49x^2+4/7x5y=1249x2+47x
y=12/245x^2+4/35xy=12245x2+435x