SOLUTION: this is a weird question to type out but basically I have to prove without using a calculator that (root)4 + (root that was above 4 continues)(root)7 [root that was above 4 ends]+

Algebra ->  Square-cubic-other-roots -> SOLUTION: this is a weird question to type out but basically I have to prove without using a calculator that (root)4 + (root that was above 4 continues)(root)7 [root that was above 4 ends]+       Log On


   

Question 159235: this is a weird question to type out but basically I have to prove without using a calculator that (root)4 + (root that was above 4 continues)(root)7 [root that was above 4 ends]+ (root)4 - (root that was above 4 continues)(root)7 [root that was above 4 ends] = (root)14
Plz help!!!
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
this is a weird question to type out but basically I have to prove without using a calculator that (root)4 + (root that was above 4 continues)(root)7 [root that was above 4 ends]+ (root)4 - (root that was above 4 continues)(root)7 [root that was above 4 ends] = (root)14
Plz help!!!
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Whenever you're asked to prove something, it might be true and it might not. Let's find out.
I assume by "root" you mean square root.
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sqrt%28%284%29%2Bsqrt%287%29%29+%2B+sqrt%28%284%29-sqrt%287%29%29+=+sqrt%2814%29
Square both sides

Collect terms
8+%2B+2%2Asqrt%28%284%29%2Bsqrt%287%29%29%2Asqrt%28%284%29-sqrt%287%29%29+=+14
Multiply the 2 radicals
8+%2B+2%2Asqrt%2816+-+7%29+=+14
8+%2B+2%2Asqrt%289%29+=+14
8 + 2*3 = 14
8 + 6 = 14
So it is true.