Divide the first equation by 2 and add the result to the second equation. This will eliminate x.
... (-4x -2y)/2 + (2x +4y) = (-12)/2 +(-12)
... 3y = -18 . . . . . collect terms
... y = -6 . . . . . . . divide by 3
Substitute this into either equation to find x. Let's use the second equation, where the coefficient of x is positive.
... 2x +4(-6) = -12
... 2x = 12 . . . . . . . . add 24
... x = 6 . . . . . . . . . . divide by 2
The solution is (x, y) = (6, -6).
Answer:
33
Step-by-step explanation:
a right angle is 90 degress since the other side is 57 than ac must be 33
Answer:
12
Step-by-step explanation:
Answer:
Will's age = 9 years
Bill's age = 11years
Step-by-step explanation:
Let will age = x
Bill = x +2 since he is 2 years older
x(x+2) = 5( x +x+2) - 1
Opening brackets
x² + 2x = 5(2x + 2) - 1
x² + 2x = 10x + 10 - 1
x² + 2x = 10x + 9
Collect like terms
x² + 2x - 10x - 9 = 0
x² - 8x - 9 = 0
Solve quadratically using factorisation method by finding two factors of +9 that can add up to give -8, the coefficient of x.
The factors are -9 and +1
x² + x - 9x - 9 = 0
x(x + 1) -9( x +1)
x+1) (x -9) =0
x + 1 = 0 or x -9 =0
x = -1 or 9
Age can not be negative
Therefore,
Will's age = 9 years
Bill's age = x+2 = 9+2 = 11years
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