GB-06-03-001 · Substitution into a quadratic

Find $y$ when $y=10x^{2} - 3x + 5$ and $x=-5$ .

Substituting into a Quadratic Expression Booklet p. 30 & p. 78

Method

1) Substitute x inside brackets: (−c)² is positive!

2) Evaluate powers first (BIRDMAS), then multiply, then add/subtract

Worked Example (GB-06-03-001)

Substitute (−5) for every x, with brackets.

270

Ans =

270