Solve the following equations for x :
1 > 8x² + 15 = 26x
2> x (2x + 5) = 25
Answers
Answered by
2
Step-by-step explanation:
8x^2+26x+15=0
{{15×15=120}}
so...
8x^2+(20+6)x+15=0
8x^2+20x+6x+15=0
4x(2x+5)+3(2x+5)=0
(4x+3)(2x+5)
x=-3/4,-5/2
Answered by
322
1 > 8x² + 15 = 26x
- (Writing as ax² + bx + c = 0)
➸ 8x² - 26x + 15 = 0
➸ 8x² - 20x - 6x + 15 = 0
➸ 4x (2x - 5) - 3(2x - 5) = 0
➸ (2x - 5) (4x - 3) = 0 (Factorising left side )
➸ 2x - 5 = 0 or 4x - 3 = 0 (Zero - product rule)
➸ x = 5/2 or x = 3/4
❖ Therefore,
- Hence, the roots of the given equation are 5/2 , 3/4.
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2 > x (2x + 5) = 25
- (Writing as ax² + bx + c = 0)
➸ 2x² + 5x - 25 = 0
➸ 2x² + 10x - 5x - 25 = 0
➸ 2x (x + 5) - 5(x + 5) = 0
➸ (x + 5) (2x - 5) = 0 (Factorising left side )
➸ x + 5 = 0 or 2x - 5 = 0 (Zero - product rule)
➸ x = -5 or x = 5/2
❖ Therefore,
- Hence, the roots of the given equation are -5 , 5/2.
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