This is a system of equations, and we can use various methods to solve it. We'll use substitution in this case. We're told:
2x + 3y = -5
5x + 2y = 4
To solve by substitution, what we need to do is take either one of those equations, and solve it for either x or y. Let's take the second one and solve it for x:
5x + 2y = 4
5x = 4 - 2y
x = (4 - 2y)/5
Now we can take that solution for x, and substitute it into the other equation:
2x + 3y = -5
2((4 - 2y)/5) + 3y = -5
(8 - 4y) / 5 + 3y = -5
(8 - 4y + 15y) / 5 = -5
8 - 4y + 15y = -25
11y = -33
y = -3
We now have a value for y, and can plug it into either of the original equations to solve for x:
2x + 3y = -5
2x + 3(-3) = -5
2x - 9 = -5
2x = 4
x = 2
To verify our answer, we can plug either x or y into the other of our original equations, and see if we get the same result for the other variable:
5x + 2y = 4
5(2) + 2y = 4
10 + 2y = 4
2y = -6
y = -3
So that confirms our answer, and the two equations intersect at the point (2, -3).
This equation has no value, as the value of n could be anything, giving this equation an infinite number of answers. To answer this equation, you either need to know what n is, or have an equals sign.
It is an equation and the value of a is 7
(4/9) x = That's not an equation. If there were a number after the 'equals' sign, then we could calculate the value of 'x'. But as it is, there's no question there, so there's nothing to solve.
40
It is an equation and the value of x is 2
This equation has no value, as the value of n could be anything, giving this equation an infinite number of answers. To answer this equation, you either need to know what n is, or have an equals sign.
It is an equation in the form of: 3x+5 = 20 and the value of x works out as 5
It is an equation and the value of a is 7
6The line of best fit has the equation = -3 + 2.5x. What does this equation predict for a value of x = 3?Answer: 4.5
(4/9) x = That's not an equation. If there were a number after the 'equals' sign, then we could calculate the value of 'x'. But as it is, there's no question there, so there's nothing to solve.
It is an equation and the value of x is -9.25
It is an equation and the value of m is 50
43
It is an equation and the value of b is 3
It is an equation and the value of n is 14
x = 9
a = Zero