5 + x = 2x _____ Four times the difference between a number and five

Answer 1

4 times the difference between a number and 5 = 4(x-5)

5+x = 2x(4(x-5)) = 2x(4x-20) = 8x^2 -40x

8x^2 -41x -5 = 0

x=41/16+/- (1/16)sqr(41^2+160)

= (41+/- sqr(1681+160))/16

=(41+/-sqr1841)/16

or 2x times 4 times difference = 2x(20-4x) = 40x -8x^2

5+x = 40x-8x^2

8x^2 -39x +5 = 0

x= 39/16 +/-(1/16)sqr(39^2 -4(8)(5))

= (39+/- sqr(1170+351-160))/16

= (30+/-sqr(1521-160)/16

= (39+/- sqr1361)/16

the "difference" of two numbers could be

x-y or y-x, usually whichever is positive