How do you solve 8x43=1x10?

1 Answer
Oct 21, 2015

x1,2=49±76

Explanation:

The first thing to notice here is that you have two values of x for which the denominators are equal to zero.

This means that any possible solution set will not include thes values. In other words, you need

x40x4 and x100x10

The next thing to do is use the common denominator of the two fractions, which is equal to (x4)(x10), to rewrite the equation without denominators.

To do that, multiply the first fraction by 1=x10x10, 3 by 1=(x4)(x10)(x4)(x10), and the second fraction by 1=x4x4.

This will get you

8x4x10x103(x4)(x10)(x4)(x10)=1x10x4x4

8(x10)(x4)(x10)3(x4)(x10)(x4)(x10)=x4(x4)(x10)

This is of course equivalent to

8x803(x214x+40)=x4

7x763x2+42x120=0

3x249x+196=0

Use the quadratic formula to find the two roots of this quadratic equation

x1,2=(49)±(49)24319623

x1,2=49±496=49±76

Therefore, you have

x1=4976=7 and x2=49+76=283

Since both solutions satisfy the condtions x4 and x10, both will be valid solutions to the original equation.