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If x^2 = 16, why isn't the answer just x = 4?

You're right that x = 4 is a solution to the equation - but the problem is it's not the only solution, x = -4 also works.You have to be careful not to take a shortcut by simply taking the square root of both...
LD
Answered by Laurie D. • Maths tutor
17966 Views

solve 2x^2+4x-7=0

Notice that this is a quadratic. First you should try factorisation, then if unsuccessful try completing the square (or the quadratic formula). In this example, factorisation is not possible (I can this furt...
KW
Answered by Katie W. • Maths tutor
8628 Views

Integrate ln(x)/(x^3)

Using integration by parts split it into v'=(1/x^3) and u=ln(x). v=-1/2x^2 and u'=1/x. Integral ln(x)/(x^3) = u*v - Integral u'*v = -ln(x)*1/2x^2 - 1/4x^2 + c
AA
Answered by Archie A. • Maths tutor
6477 Views

Find the integral of (x+4)/x(2-x) .dx

In order to integrate the expression we must first rewrite it in terms of Partial Fractions i.e. A/x and B/(2-x), so that when multiplied together we have a fraction with same denominator as the expression w...
AT
Answered by Aaron T. • Maths tutor
4698 Views

Solve the simultaneous equations: y=x/2 + 2 and 2y+3x=12

Label the equations (1): y=x/2 + 2 and (2): 2y+3x=12. Firstly, multiply equation (1)by 2, this will give you (1a): 2y=x+4, then, substitute (1a) into (2). This gives you (x+4)+3x=12. Therefore, 4x+4=12. 4x=1...
JB
Answered by Joseph B. • Maths tutor
6718 Views