If you mean: 5.6x = 39.76 then x = 7.1 If you mean: 5.6 times 39.76 then the product is 222.656
84x2=168. There are other solutions. 56x3=168. 42x4=168. 28x6=168. 24x7=168. 21x8=168. 14x12=168.
3/7x + 5 = 87x(3/7x + 5) = 8(7x)3(7x/7x) + (7x)(5) = 8(7x)3 + 35x = 56x3 + 35x - 35x = 56x - 35x3 = 21x3/21 = 21x/211/7 = x
You didn't state what the problem is. Quite often you will want to either factor it, or solve the equation (in this case) 56x3 - 170x2 + 98x = 0. In this case, first take out the common factor "x". Then use the quadratic formula on what is left. (If, for example, 5 is a solution, then x - 5 is a factor.)