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Cross multiplication method, find the value z and y for 3x + 5y = 70 and 7x-3y =60

User Faulty Orc
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1 Answer

2 votes

Answer:

Y=7.05

X= 11.6

Explanation:

Equate both equations to zero

3x+5y=70--------equation 1

7x-3y=60---------equation 2

From the equation above

a1=3, b1=5, c1=-70

a2=7, b2= -3, c2=-60

By applying the cross multiplication method

x/b1c2-b2c1= y/a2c1-a1c2= 1/a1b2-a2b1

x/(5)(-60)-(-3)(-70)=y/(7)(-70)-(3)(-60)=1/(3)(-3)-(7)(5)

x/-300-(-210)=y/-490-(-180)=1/-9(-35)

x/-510=y/-310=1/-44

x/-510=1/-44 , y/-310=1/-44

-44x=-510 , -44y= -310

x=11.6 , y=7.05

Thus, the value of x is 11.6 and the value of y is 7.05

User Cjsimon
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