Question

Does not (17+r)^2 equal 289 +r^2?

Answer 1

So the problem is
r^2 + 24^2 = (17 + r)^2

Answer 2

My teacher says it's is wrong.

Answer 3

No, \[(a+b)² = a² + 2ab + b²\]. So, \[(17 + r)² = 17² + 2*17*r + r² = 279 + 34r + r²\]

Answer 4

It's not 279 in my answer, its 289, sorry...

Answer 5

whoops yeah i typed it wrong

Answer 6

but wouldn't (r)^2 equal r^2?

Answer 7

It depends. For example:
\[(-3)² = 9\]\[-3² = -9\]

Answer 8

where did the 2 x 17 x r come from?

Answer 9

oh

Answer 10

Like i said,
\[(a+b)² = a² + 2ab + b²\]
Changing a to 17 and b to r, you wil have:\[(17 + r)² = 17² + 2*17*r + r²\]

Answer 11

oh... i guess that makes sense...

Answer 12

You can see doing:
\[(17 +r)²=(17+r)(17+r)=17*17+17r+17r+r² = 289 + 34r +r²\]

Answer 13

ah! got it now! thanks!