If 3x-y=5 and 2x+y= 15, evaluate x^2+2yx

72

Step-by-step explanation:

3x-y=5 and 2x+y= 15

Add the two equations together to eliminate y

3x-y=5

2x+y= 15

5x = 20

Divide by 5

5x/5 = 20/5

x = 4

Now we can find y

2x+y = 15

2(4) +y = 15

8+y =15

Subtract 8 from each side

8+y-8 = 15-8

y =7

We want to find

x^2+2xy

(4)^2 +2(4)(7)

16+56

72

72

Step-by-step explanation:

3x-y=5

2x+y= 15

Adding the two equations,

5x = 20

x = 4

3(4) - y = 5

y = 12 - 5

y = 7

x² + 2yx

(4)² + 2(4)(7)

16 + 56

72

answer: solve 5\cdot 2^x=2405⋅2  

x

=2405, dot, 2, start superscript, x, end superscript, equals, 240.

solution

to solve for xxx, we must first isolate the exponential part. to do this, divide both sides by 555 as shown below. we do not multiply the 555 and the 222 as this goes against the order of operations!

\begin{aligned} 5\cdot 2^x& =240 2^x& =48 \\ \end{aligned}  

5⋅2  

x

2  

x

​    

=240

=48

​

step-by-step explanation: