+0

# Algebra

0
131
1

Find a monic quartic polynomial f(x) with rational coefficients whose roots include x=1-sqrt2 and x=2+sqrt7. Give your answer in expanded form.

Nov 14, 2021

#1
+13721
+1

rational coefficients

Hello Guest!

$$f(x)=(x-1+\sqrt{2} )\times (x-2-\sqrt{7})\\ f(x)=(x^2-2x-x\sqrt{7}-x+2+\sqrt{7}+x\sqrt{2}-2\sqrt{2} -\sqrt{2\cdot 7})\\ f(x)=x^2+(-2-\sqrt{7}-1+\sqrt{2})x+\sqrt{7}-2\sqrt{2} -\sqrt{2\cdot 7}$$

$$f(x)=x^2-4.2315x-5.1559$$

Does the function with rational coefficients exist? I do not think so.

!

Nov 14, 2021
edited by asinus  Nov 15, 2021