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put this solution on YOUR website!1> m^2 + 4m - 21 = (m+7) (m-3)
2> 2x^3 +5x^2 - 12x = 0
Removing x as the common factor, the above equation becomes,
x(2x^2 + 5x - 12) = 0
==> x [ 2x^2 +8x - 3x - 12 ] = 0 [splitting the middle term]
==> x[ 2x(x+4) -3(x+4) ] = 0 [taking out the common factor]
==> x(x+4) (2x-3) = 0
==> either x = 0 or x+4 = 0 or 2x - 3 = 0
==> x = 0 or x = -4 or x = 3/2 [2x-3 = 0==>2x = 3 or x = 3/2]
3> 2y^2 = -3y + 35
Adding 3y-35 to both the sides,
2y^2 + 3y - 35 = 0
==> 2y^2 + 10y - 7y - 35 = 0 [splitting the middle term]
==> 2y(y + 5) - 7(y + 5) = 0
==>(y + 5) (2y - 7) = 0
==> y+5 = 0 or 2y - 7 = 0
==> y = -5 or y = 7/2
4> (4x-3)(4x+3)
= (4x)^2 - 3^2 [as (a+b)(a-b) = a^2 - b^2]
= 16x^2 - 9
Good Luck!!!
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