2007-12-23 04:41:25 · 3 answers · asked by delightfulldee71 1 in Science & Mathematics ➔ Mathematics
x ² - 7 x + 8 = 0
x = [ 7 ± √ (49 - 32) ] / 2
x = [ 7 ± √ (17) ] / 2
2007-12-23 04:55:05 · answer #1 · answered by Como 7 · 1⤊ 0⤋
Bring all the terms to one side:
x² - 7x + 8 = 0
Think: What two numbers multiply to 8 and add to -7?
There aren't any, so you must use the quadratic formula:
x = [7 ± â((-7)² - 4(1)(8))] / 2(1)
x = [7 ± â17] / 2
x = approx. 5.561552913 or x = approx. 1.438447187
2007-12-23 12:45:47 · answer #2 · answered by Jacob A 5 · 1⤊ 0⤋
subtract 7x and add 8 for both sides
x^2 - 7x + 8 = 0
quadratic fomula:
x = -b ± â(b^2 - 4ac)
----------------------------
............... 2a
where a = 1
b = -7
c = 8
now plug in chunks
x = -(-7) ± â((-7)² - 4(1)(8))
-----------------------------------
............ 2(1)
x = 7 ± â(49 - 32)
..... ------------------
.............. 2
x = [7 屉(17)]/2 <== answer
2007-12-23 12:56:37 · answer #3 · answered by Anonymous · 0⤊ 1⤋