The value of the expression 3x + 5y will be 47.
How to calculate the equation?
It should be noted that an equation is used in Mathematics to show the relationship the exist between different variables.
The given equations are:
x - 4y = -10 ...... i
2x + 9y= -3 ....... ii
Multiply equation i by 2
Multiply equation ii by 1
2x - 8y = -20 ...... iii
2x + 9y = -3. ..... iv
Subtract equation iv from iii
(2x - 2x) (-8y - 9y) = (-20 + 3)
-17y = -17
Then, we have to divide by the coefficient.
y = -17/-17
y = 1
Since x - 4y = -10.
We will then put the value of y = 1 into the equation
x - 4(1) = 10
x = 10 + 4
x = 14
Therefore, 3x + 5y will be:
=3(14) + 5(1)
= 42 + 5
= 47.
In conclusion, the value of 3x + 5y is 47.
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