5x+7y=31 2x+4y=16 Which of the following systems could be used to solve the given system of equations by the addition method? 10
1 answer:
Equation 1: 
Equation 2:
We can either use the 'elimination' method or the 'substitution' method to solve this simultaneous equation.
In some cases one method is easier to use than the other. For this one, it would be easier to use the elimination method
We need to eliminate either the 'x' or the 'y' to begin with. Say we want to eliminate the 'x' terms, then the next step is to make the constant the same
Equation 1: the constant of 'x' is 5
Equation 2: the constant of 'x' is 2
To make the two constants the same, think of common multiple. The lowest common multiple for 5 and 2 is 10
Equation 1: Multiply all terms by 2 to achieve 10x
Equation 2: Multiply all terms by 5 to achieve 10x
Equation 1:
Equation 2:
Once the constant of 'x' is the same, then we can start the elimination process. Since our aim is to eliminate, one of the 'x' need to be in negative form. We can either multiply Equation 1 or Equation 2 by (-1)
Equation 1: -10x - 14y = -62
Equation 2: 10x + 20y = 80
Hence the correct answer is: Third option
Equation 2:
We can either use the 'elimination' method or the 'substitution' method to solve this simultaneous equation.
In some cases one method is easier to use than the other. For this one, it would be easier to use the elimination method
We need to eliminate either the 'x' or the 'y' to begin with. Say we want to eliminate the 'x' terms, then the next step is to make the constant the same
Equation 1: the constant of 'x' is 5
Equation 2: the constant of 'x' is 2
To make the two constants the same, think of common multiple. The lowest common multiple for 5 and 2 is 10
Equation 1: Multiply all terms by 2 to achieve 10x
Equation 2: Multiply all terms by 5 to achieve 10x
Equation 1:
Equation 2:
Once the constant of 'x' is the same, then we can start the elimination process. Since our aim is to eliminate, one of the 'x' need to be in negative form. We can either multiply Equation 1 or Equation 2 by (-1)
Equation 1: -10x - 14y = -62
Equation 2: 10x + 20y = 80
Hence the correct answer is: Third option
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Answer:
s = 16.97 units
Step-by-step explanation:
Since this is a right triangle, we can use trigonometry to figure out the lengths of the sides.
Look at the 45 degree angle. We can use the opposite side (12) and the hypotenuse (s) to solve for s.
Opposite and hypotenuse is sine, so we are using sine. The sine of 45 degrees is 0.70710678118. Make an equation like so:
- 0.70710678118 =
, and we are solving for s.
Put a 1 in the denominator of sine(45 degrees) so you can cross-multiply.
Cross multiply.
- 0.70710678118s = 12
Divide both sides by sine(45 degrees).
- s = 16.97
The length of side s is 16.97 units.
Another way to have done this problem is to use the Pythagorean theorem: a^2 + b^2 = c^2
Substitute 12 for a and b and solve for c, the hypotenuse.
- (12)^2 + (12)^2 = c^2
Evaluate the exponents.
- 144 + 144 = c^2
Add them together.
- 288 = c^2
Square root 288 to solve for c.
c = 16.97, which is the same answer as you got using trigonometry.