SOLUTION: how do you solve 5y^4-7=73

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Question 223459: how do you solve 5y^4-7=73
Found 2 solutions by Earlsdon, MathTherapy:
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for y:
5y%5E4-7+=+73 Add 7 to both sides.
5y%5E4+=+80 Divide both sides by 5.
y%5E4+=+16 Take the fourth root of 16. 16+=+2%5E4
highlight%28y+=+2%29 or highlight%28y+=+-2%29
You really get four solutions to this quartic equation, two pairs of double roots.
2, 2, -2, and -2

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
how do you solve 5y^4-7=73

5y%5E4-7=73
5y%5E4+-+80+=+0
5%28y%5E4+-+16%29+=+5%280%29%29 ----- Factoring out the GCF, 5
%28y%5E2+-+4%29%28y%5E2+%2B+4%29+=+0 ------ Factoring y%5E4+-+16
%28y+-+2%29%28y+%2B+2%29%28y%5E2+%2B+4%29+=+0 ------ Factoring y%5E2+-+4

y+-+2+=+0 ; y+%2B+2+=+0 ; y%5E2+%2B+4+=+0

highlight_green%28y+=+2%29 or highlight_green%28y+=+-+2%29 or y%5E2+=+-+4 ----- sqrt%28y%5E2%29+=+sqrt%28-4%29 ------ y+=+sqrt%28-+1%2A4%29 ------ y+=_%2B-+sqrt%28-+1%2A2%5E2%29 ----- highlight_green%28y+=+2i%29 or highlight_green%28y+=+-+2i%29