solve the equation by factorising
2007-06-04 04:38:33 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
(2x-5)*(2x+3)
2007-06-04 04:42:19 · answer #1 · answered by roynburton 5 · 0⤊ 0⤋
4x^2 - 4x -15 =0
To solve such types of problems, one can also use the quadratic formula, but that is a huge pain. A simpler way, but one which only works for certain problems, is to multiply the constant of the x^2 with the constant, in this case, 4 * -15 = - 60
Now, we want to break down the middle term so that the two terms, on multiplying will equal -60. In this case, -10x + 6x.
so,
4x^2 - 4x -15 =0
or, 4x^2 - 10x +6x -15 =0
we then take the common terms of the first two and last two terms,
or, 2x(2x - 5) + 3(2x-5)=0
or, (2x-5)(2x+3) = 0
hence, x = -3/2, 5/2
2007-06-04 11:48:19 · answer #2 · answered by shekum 2 · 0⤊ 0⤋
-3/2 or 5/2
2007-06-04 11:46:23 · answer #3 · answered by Romeotheriault 1 · 0⤊ 0⤋
(2x - 5).(2x + 3) = 0
x = 5/2 , x = - 3/2
2007-06-04 11:50:49 · answer #4 · answered by Como 7 · 0⤊ 0⤋
4x^2-4x-15=0
(2x-5)(2x+3)=0
x=5/2
x=-3/2
2007-06-04 11:48:03 · answer #5 · answered by Anonymous · 0⤊ 0⤋