Question 972553
The sum of twice the square of a number and 7 times the number equals 15. What is the number?
2x^2 + 7x = 15
2x^2 + 7x - 15 = 0
2x^2 + 10x-3x - 15 = 0
2x(x+5)-3(x+5) = 0
(x+5)(2x-3) = 0
x = -5 or x = 3/2
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Twice the square of a number equals the sum of 5 times the number and 17. Find the number.
2x^2 = 5x+17
2x^2 - 5x - 17 = 0
x = [5 +- sqrt(25-4*2*-17)]/4
x = [5+-sqrt(161)]/4
x = [5+-12.69]/4
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One number is 3 larger than another and the sum of their square is 269.Find the number.
a = b + 3
a^2 + b^2 = 269
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(b+3)^2 + b^2 = 269
2b^2 + 6b = 260
b^2 + 3b -130 = 0
(b+13)(b-10) = 0
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If b = -13, a = -10
If b = 10, a = 13
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Cheers,
Stan H.
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