I need to solve using the substitution method, but I'm having trouble figuring out how to do it with this problem. 2y=x^{2 }and y=4x^{3} Aug 12 | Alex from Houston, TX | 1 Answer | 0 Votes Mark favorite Subscribe Comment
Alex: First equation gives y = x^{2} / 2. So x^{2} / 2 = 4 x^{3}, giving x = 1 / 8 and y = x^{2} / 2 = 1/128. Check y = 4x^{3} = 4(1/512)= 1/ 128, 2y = 1/64 and x^{2 }= (1/8)^{2} = 1/64. Dattaprabhakar (Dr.G.) Aug 12 | Dattaprabhakar G. Comment Comments I can't figure out how to get the x = 1/8 I know how to get x^{2}/2 = 4x^{3} but I don't understand how that becomes 1/8 Thank you for the help! Aug 12 | Alex from Houston, TX x^{2} / 2 = 4 x^{3}. Divide both sides by x. (Note that x = 0 is a solution but not interesting. So look for non-zero solutions. Then you can divide by x on both sides.) You get 1 / 2 = 4 x. Divide both sides by 4. You get 1 / 8 = x. This is the same as x = 1 / 8. Do you follow? Dattaprabhakar (Dr. G.) Aug 13 | Dattaprabhakar G. Comment
I can't figure out how to get the x = 1/8 I know how to get x^{2}/2 = 4x^{3} but I don't understand how that becomes 1/8 Thank you for the help! Aug 12 | Alex from Houston, TX
x^{2} / 2 = 4 x^{3}. Divide both sides by x. (Note that x = 0 is a solution but not interesting. So look for non-zero solutions. Then you can divide by x on both sides.) You get 1 / 2 = 4 x. Divide both sides by 4. You get 1 / 8 = x. This is the same as x = 1 / 8. Do you follow? Dattaprabhakar (Dr. G.) Aug 13 | Dattaprabhakar G.
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