Question

Can someone be nice enough
To help me with these problems

Simplify The problems below
X^2+51=100


2X^2-7X+9=0

Answer 1

@Zale101

Answer 2

@loser66

Answer 3

for the 1st question

subtract 51 from both sides of the equation

then take the square root of the answer...

there are 2 solutions, the positive and negative versions..

2nd question needs the general quadratic formula

\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]

you have a = 2, b = -7 and c = 9

substitute them and calculate the answers

Answer 4

okay thank you so much

Answer 5

so for the first one would it equal 7 squared ? @campbell_st

Answer 6

well yes but the answers are x = -7 as (-7)^2 = 49 and x = 7

Answer 7

oh okay thank you

Answer 8

For the second one i got \[-7\pm \sqrt{-23} \over 4\]

Answer 9

that looks correct, you make need to use the complex number

\[i^2 = -1\]

and dix the leading term so its

\[x = \frac{7 \pm \sqrt{23i^2}}{4} = \frac{7 \pm i \sqrt{23}}{4}\]

Answer 10

why do we have to use the complex number ?

Answer 11

because you can't take the square root of a negative.... if you do it on a calculator you get math error... or some other error message.

Answer 12

oh alright thank you, now I understand it much better.