Substitution into a formula

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Quandaries & Queries

Question from beth, a student:

Given q(x) = 7xsquared + 9, find q(-7)

This is the way the question is written. On 7x the x is squared. I didn't know how to make the 2 up above the x.

These were the choices I had for the answers to this problem
1.) 343
2.) -40
3.) 334
4.) -89
5.) 352

Hi Beth,

Suppose p(x) = 5x² + 2x + 7 then

p(-4) = 5 × (-4)² + 2 × (-4) + 7
= 5 × 16 + (-8) + 7
= 80 - 8 + 7
= 79

Now can you find q(-7) is q(x) = 7x² + 9?

Penny

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