$(a-b)^2=a^2-2ab+b^2\\\\2x^2-4x-9=0\qquad|\text{add 9 to both sides}\\\\2x^2-4x-9+9=0+9\\\\2x^2-4x=9\qquad|\text{divide both sides by 2}\\\\\dfrac{2x^2}{2}-\dfrac{4x}{2}=\dfrac{9}{2}\\\\x^2-2x=4.5\\\\x^2-2\cdot x\cdot1=4.5\qquad|\text{add}\ 1^2\ \text{to both sides}\\\\x^2-2\cdot x\cdot1+1^2=4.5+1^2\\\\(x-1)^2=5.5\iff x-1=\pm\sqrt{5.5}\qquad|\text{add 1 to both sides}\\\\x=1-\sqrt{5.5}\ \vee\ x=1+\sqrt{5.5}$

4 0

3 years ago

A washer and a dryer cost 860 combined. The washer costs 90 less than the dryer. What is the cost of the dryer?

Kipish [7]

Answer:

340

Step-by-step explanation:

860 ÷ 2 = 430

430 - 90 = 340

4 0

2 years ago

Compute x/y if

Ivenika [448]

Answer:

Y = 1/4x-1

X = 4y-1

Step-by-step explanation:

layout the equations :

x+1/y = 4 y+1/x = 1/4

solve the equations, remember to switch sides switch signs solving the equations will give us the value of the letter

x+1/y = 4

x+1 = 4y

x=4y-1

***

y+1/x = 1/4

y+1 = 1/4x

y = 1/4x-1

4 0

2 years ago

Read 2 more answers

Some of the dimensions of a square pyramid are shown in the diagram. The height of the pyramid is 7.5 meters. square pyramid Wha

Naddika [18.5K]

Answer:

i think the answer is 2.5 but im not 100% sure if it is.

Step-by-step explanation:

50/50 chance.

5 0

2 years ago