What is the solution of the set?

Mathematics

1 answer:

ziro4ka [17]3 years ago

3 0

$x^2=16-4x\ \ \ |+4x\\\\x^2+4x=16\ \ \ \ |+2^2\\\\\underbrace{x^2+2\cdot x\cdot2+2^2}_{(a+b)^2=a^2+2ab+b^2}=16+2^2\\\\(x+2)^2=20\iff x+2=\pm\sqrt{20}\\\\x+2=-\sqrt{4\cdot5}\ \vee\ x+2=\sqrt{4\cdot5}\ \ \ |-2\\\\x=-2-2\sqrt5\ \vee\ x=-2+2\sqrt5$

Answer: D.

You might be interested in

I came in super late

Allushta [10]

Since we know that 1/4 is equal to 25%, or 0.25 in decimal form, we are able to work with 0.75 in the expression.

We are told to use j as the original price of the jeans, so we can set up the expression:

$j-0.25j$

to represent the cost of the jeans with the discount.

Then to simplify, we simply take out j as a common factor, and solve what's in the parentheses:

$j(1-0.25)$

$j(0.75)$ or $0.75j$

Using this equation, we can solve for the b part of the question. If the pair of jeans originally costs $60, plug in 60 to where j is in the expression:

$0.75j$

$0.75(60)=45$