Monday

September 1, 2014

September 1, 2014

Posted by **Jenny** on Monday, September 1, 2008 at 9:35pm.

2x^2-18x=0, x^2=6x+7, 6y^2+5y-6=0

Also

SOLVE FOR X CORRECT TO 4 DECIMAL PLACES:

x^2+6x+2=0 2x+4=3x^2

- Algebra -
**David Q**, Tuesday, September 2, 2008 at 3:03pmFor the first bit of the question, get all the terms over onto the left-hand side of the equation. For example, take the second one:

X²-6X-7=0

Usually you can factorize it easily into the following form: (X+A)(X+B). (There's no guarantee that it's an easy factorization, but if you're expected to solve it this way it usually is.)

If you multiply out those two brackets, you'll get X² + (A+B)X + AB.

So in this example, if you compare the corresponding terms from the two equations, A + B = -6 and AB = -7. So what are A and B? Usually you can spot it in a few seconds...

How about A = 1 and B = -7?

One down, two to go...

**Related Questions**

Math - i forgot how to solve problems like this... 2x^2-18x=0, x^2=6x+7, 6y^2+5y...

algebra 2 - Solve the equation for x. Round your answer to two decimal places. ...

Algebra 1 - What is 28% as a decimal and as a fraction? Also, can you tell me ...

math,bobpursley - Is this the correct way to solve these math problems and are ...

Math - Solve the exponential equation. Use a calculator to obtain a decimal ...

Math - thanks for the answers, but I need to know how to solve the problems, so ...

algebra - give exact and approximate solutions to three decimal places for x^2+...

algebra - Give exact and approximate solutions to three decimal places x^2+18x+...

Math - Solve for x,correct to TWO decimal places 4+5x>6x to the power 2

math - solve the equation giving your answer in correct to 2 decimal places 5x ...