SOLUTION: Solve 2x-y=9 and 7x+4y=1 by using the substitution method.

Question 416366: Solve 2x-y=9 and 7x+4y=1 by using the substitution method.
Answer by krice134(1) (Show Source): You can put this solution on YOUR website!
2x-y=9,7x+4y=1
Since 2x does not contain the variable A letter used to represent a number value in an expression or an equation. to solve for, move it to the right-hand side of the equation A mathematical statement that says two expressions have the same value; any number sentence with an = . by subtracting 2x from both sides. -y=-2x+9 7x+4y=1
To compute a product; to perform a multiplication. Any expression written as a product or quotient. Example: 2xy , , or in the equation A mathematical statement that says two expressions have the same value; any number sentence with an = . by -1.
-y � -1=-2x � -1+9 � -1 7x+4y=1
multiply To compute a product; to perform a multiplication. -y by -1 to get y.
y=-2x � -1+9 � -1 7x+4y=1
Simplify the right-hand side of the equation A mathematical statement that says two expressions have the same value; any number sentence with an = . by multiplying out all the term Any expression written as a product or quotient. y=2x-9 7x+4y=1
Replace all occurrences of y with the solution The value of a variable that makes an equation true. found by solving the last equation A mathematical statement that says two expressions have the same value; any number sentence with an = . for y. In this case, the value substituted is 2x-9.
y=2x-9
7x+4(2x-9)=1
Multiply To compute a product; to perform a multiplication. 4 by each term Any expression written as a product or quotient. Example: 2xy , , or inside the parentheses y=2x-9 7x+8x-36=1 Since 7x and 8x are like term Any expression written as a product or quotient. Example: 2xy , , or , add 8x to 7x to get 15x y=2x-9
15x-36=1
Since -36 does not contain the variable A letter used to represent a number value in an expression or an equation. to solve for, move it to the right-hand side of the equation A mathematical statement that says two expressions have the same value; any number sentence with an = . by adding 36 to both sides.
y=2x-9
15x=36+1
Add 1 to 36 to get 37.
y=2x-9
15x=37
divide To perform the operation of division. each term Any expression written as a product or quotient. Example: 2xy , , or in the equation A mathematical statement that says two expressions have the same value; any number sentence with an = . by 15.
y=2x-9
To add fractionsGlossaryfraction A number used to name a part of a group or a whole. The number below the division line is the denominator, and the number above the division line is the numerator. , the denominatorsGlossarydenominator The bottom part of a fraction. must be equal. The denominatorsGlossarydenominator The bottom part of a fraction. can be made equal by finding the least common denominatorGlossarydenominator The bottom part of a fraction. (LCD). In this case, the LCDGlossaryLCD L east C ommon D enominator; the smallest multiple of the denominators of two or more fractions. is 15. Next, multiplyGlossarymultiply To compute a product; to perform a multiplication. each fractionGlossaryfraction A number used to name a part of a group or a whole. The number below the division line is the denominator, and the number above the division line is the numerator. by a factorGlossaryfactor One of two or more expressions that are multiplied together to get a product. of 1 that will create the LCDGlossaryLCD L east C ommon D enominator; the smallest multiple of the denominators of two or more fractions. in each of the fractionsGlossaryfraction A number used to name a part of a group or a whole. The number below the division line is the denominator, and the number above the division line is the numerator.
This is the solution The value of a variable that makes an equation true. to the system of equation A mathematical statement that says two expressions have the same value; any number sentence with an = Answer is y=61/15, x=37/15

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