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Anton [14]
3 years ago
11

A student bought a calculator and a textbook for a course in algebra. He told his friend that the total cost was $115 (without t

ax) and that the calculator cost $20 more than four times the cost of the textbook. What was the cost of each item? Let x= the cost of a calculator and y= the cost of the textbook. The corresponding modeling system is {x+y=115x=4y+20. Solve the system by using the method of substitution.
Mathematics
1 answer:
Marrrta [24]3 years ago
5 0

Answer:

X=$96

Y=$19

Step-by-step explanation:

x=4y+20

X+Y=$115

4Y+20+Y=$115

5Y+20=$115

-20 -20

5Y=$95

/5 /5

Y=$19

X=4 x $19 + $20

X=$76+$20

X=$96

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zloy xaker [14]

Step-by-step explanation:

We are asked to simply (2√5 + 3√2)². Using formula: (a + b)² = a² + b² + 2ab. Let's say 2√5 = a, 3√2 = b. So,

→ (a + b)² = a² + b² + 2ab

→ (2√5 + 3√2)² = (2√5)² + (3√2)² + 2(2√5)(3√2)

We are aware about the fact that root means 1/2 and square of root means 2/2 that is 1. Using this we get:

→ (2√5 + 3√2)² = 4(5) + 9(2) + 2(2√5)(3√2)

Solve the brackets, to do so first put the like terms in one box.

→ (2√5 + 3√2)² = 4(5) + 9(2) + 2(2*3)(√5)(√2)

Solve the rest calculations.

→ (2√5 + 3√2)² = 20 + 18 + 2(6)(√10)

→ (2√5 + 3√2)² = 38 + 12√10

Option (a) (38 + 12√10) is the correct option.

4 0
3 years ago
Read 2 more answers
The golden ratio is a solution to a quadratic equation.
Crank

Answer:

Below.

Step-by-step explanation:

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Φ2 − Φ = 1

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(Φ - 0.5)^2 = 1.25

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b. I used Completing the square.

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Please I need like an explanation of how it was done.
a_sh-v [17]

Answer:

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