solve sqrt{7x+2}= 2x and then check answers.

Question

anonymous · Answer

As with the last one, square both sides (and remember that when you do so, you have to choose the answers carefully at the end):

$$\sqrt{7X+2} = 2x$$

$$7X + 2 = 4X^{2}$$

$$4X^{2} - 7X - 2 = 0$$

anonymous · Answer

$$(\sqrt{7x+2})^2=(2x)^2$$

anonymous · Answer

this one gives a solution, unlike last one

anonymous · Answer

You'll note that when you solve the quadratic equation you'll get x=2, x=-1/4; that's because we squared both sides. But you can't have the square root of a negative number, so disregard x=-1/4

anonymous · Answer

elai will work it out

anonymous · Answer

oh because 
$$4x^2-7x-2=(x-2)(4x+1)=0$$

anonymous · Answer

so x = 2 is your answer but you have to check it in original equation 
$$\sqrt{7\times 2+2}=2\times 2$$
$$\sqrt{16}=4$$
$$4=4$$

anonymous · Answer

so i only get one answer of 2 right? nd it turns out to be right?(:

anonymous · Answer

yes one answer only and it is x = 2