## anonymous 5 years ago pefrom the indicated operation. wirte the result in the from atbi: (7+9i)(7-9i)

1. anonymous

corecction a+bi

2. watchmath

Using the identity that $$(a+b)(a-b)=a^2-b^2$$ we simplify the expression into $$7^2-(9i)^2=49+81=130$$

3. anonymous

$(7+9i)(7-9i)=49+81=130$

4. anonymous

a bag of battiries contains 5 batteries which are all the same size and equally selected. each battery is a different brand. if u selected 4 at ramdom. use the wingspaning pricinclple to determine how many points will be in the sample space with or without?

5. anonymous

You beat me to it watchmath :)

6. anonymous

factor by grouping: 6st+21t-10s-35

7. anonymous

$6st+21t-10s-35=(6st-10s)+(21t-35) =2s(3t-5)+7(3t-5)$ $=(3t-5)(2s+7)$

8. anonymous

x=√4x+12 solve √=this is a square root sign

9. anonymous

how do i give medals. id give you a milllion

10. anonymous

Subtract 12 from both sides, and then square both sides.

11. anonymous

12. anonymous

i cant find it!

13. anonymous

$x=\sqrt{4x}+12 \implies (x-12)^2=4x \implies x^2-24x+144-4x=0$ $\implies x^2-28x+144=0$ Now, use the quadratic formula to solve the equation.

14. anonymous

found the buttoN! lol

15. anonymous

given f(x)=x^2-4x-6, find f(2)

16. anonymous

$f(x)=x^2-4x-6 \implies f(2)=2^2-4(2)-6=4-8-6=-10$

17. anonymous

perform the indicated operation and simplify: 3/t+5/r-6 the division sign means over

18. anonymous

Are you sure about the expression?

19. anonymous

oh sorry its 3/r + 5/r-6

20. watchmath

$$\frac{3(r-6)}{r(r-6)}+\frac{5r}{r(r-6)}=\frac{8r-18}{r(r-6)}$$

21. anonymous

simplify and add or subratct wherever possible: √3-6√12=4√192