How do you solve #2x^2 + 2x = 60#?
1 Answer
Apr 20, 2016
x = -6 , x = 5
Explanation:
Since this is a quadratic equation, we wish to equate the terms to zero , before solving.
#rArr 2x^2 + 2x - 60 = 0 # and to solve , we must factorise, remove a common factor of 2.
hence:
# 2(x^2 + x - 30) = 0 # To factor the quadratic , look for 2 factors which multiply to -30 and sum to 1 ( the coefficient of the x-term).
These are +6 and - 5
thus
# x^2 + x - 30 = (x + 6)(x - 5)#
#rArr 2(x + 6)(x - 5 ) = 0 " has to be solved "# Now 2 ≠ 0
solve (x + 6) = 0 → x = -6
and solving (x - 5) = 0 → x = 5
solutions are
#color(red)(|bar(ul(color(white)(a/a)color(black)( x = - 6 and x = 5 )color(white)(a/a)|)))#