An equation is formed of two equal expressions. In the two of the given equations, the value of x and y are 10 and 10, respectively. The correct option is D.
What is an equation?
An equation is formed when two equal expressions are equated together with the help of an equal sign '='.
Given the two of the equation, which can be named as,
4x+5y=90 ...... equation 1
x+y=20 ............ equation 2
Solve the second equation for x,
x + y = 20
x = 20 - y ................ equation 3
In the first equation substitute the value of x from the third equation,
4x + 5y = 90
4(20 - y) + 5y = 90
Solving the equation for y,
80 - 4y + 5y = 90
y = 90 - 80
y = 10
Substitute the value of y in the second equation, to get the value of x,
x + y = 20
x + 10 = 20
x = 20 - 10
x = 10
Hence, In the two of the given equations, the value of x and y are 10 and 10, respectively.
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