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3 years ago

Solve for x: x^2-2x=15

Mathematics

1 answer:

Lyrx [107]3 years ago

5 0

Answer:

Step-by-step explanation:

x^2 - 2x = 15

x^2 - 2x - 15 = 15 - 15 (Subtract 15 from both sides.)

x^2 - 2x -15 = 0 (Simplify.)

<em />

<em>Set up & solve for a quadratic formula</em>

<h3><em>* I will solve for your first x</em></h3>

2 + root 64 / 2x 1 = 2 + root 64 / 2

root 64 = 8

= 2 + 8 / 2

= 10 / 2

= 5

<em>To solve for the second, follow the same pattern/formula for the first that I used to get 5.</em>

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Last year, Susan had 10,000 to invest. She invested some of it in an account that paid 6%

katrin2010 [14]

Answer:

In the account that paid 6% Susan invest $\$6,000$

In the account that paid 5% Susan invest $\$4,000$

Step-by-step explanation:

we know that

The simple interest formula is equal to

$I=P(rt)$

where

I is the Final Interest Value

P is the Principal amount of money to be invested

r is the rate of interest

t is Number of Time Periods

Part a) account that paid 6% simple interest per year

in this problem we have

$t=1\ years\\ P=\$x\\r=0.06$

substitute in the formula above

$I1=x(0.06*1)$

$I1=0.06x$

Part b) account that paid 5% simple interest per year

in this problem we have

$t=1\ years\\ P=\$10,000-\$x\\r=0.05$

substitute in the formula above

$I2=(10,000-x)(0.05*1)$

$I2=500-0.05x$

we know that

$I1+I2=\$560$

substitute and solve for x

$0.06x+500-0.05x=560$

$0.01x=560-500$

$0.01x=60$

$x=\$6.000$

therefore

In the account that paid 6% Susan invest $\$6,000$

In the account that paid 5% Susan invest $\$4,000$

6 0

3 years ago

Prove the trig identity: (tanx/1+secx)+(1+secx/tanx)=2cscx

lakkis [162]

=[(sinx/cosx)/(1+1/cosx)] + [(1+1/cosx)/(sinx/cosx)]

=[(sinx/cosx)/(cosx+1/cosx)]+[(cosx+1/cosx)/(sinx/cosx)]

= [sinx/(cosx+1)] + [(cosx+1)/sinx]

= [sin^2x+(cosx+1)^2] / [sinx (cosx+1)]

= [2+2cosx] / [sinx(cosx+1)]

=[2(cosx+1)] / [sinx (cosx+1)]

= 2/sinx

= 2 cscx

(I think this will be helpful for you. if you can see the picture, it has more detail in it.)