maths question.?

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Solve the equation 7a^2 + 12a - 11 = 0, giving your answer to two decimal places.

2007-08-13 12:54:11 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

Use the quad eqn:
a = {-12 +- sqr[12^2 - 4(7)(-11)]}/2(7)
= {-12 +- sqr[144 + 308]}/14
= {-12 +- sqr[452]}/14
= {-12 +- 21.26}/14 = 9.26/14, -33.26/14
= 0.66, -2.38

2007-08-13 13:11:53 · answer #1 · answered by kellenraid 6 · 0⤊ 0⤋

Do you mean 7a squared + 12a -11=0

Look up the formula for the binomial theorem. and insert the equation into the formula.

2007-08-13 20:22:01 · answer #2 · answered by Bibs 7 · 0⤊ 0⤋

use quadratic formula: [-12 +/- sqrt(144 + 4x77)]/14 =
(-12 - 21.26)/14 or (-12+21.26)/14 = 2.38, .66

2007-08-13 20:14:46 · answer #3 · answered by John V 6 · 0⤊ 0⤋