book Maths Puzzle Numerical Ability

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Problem #39: 2x+4=8

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book Other Question

The altitude to the base of an isosceles triangle _______ longer than a leg of the triangle.

a)must be
b)may be
c)cannot be
solve each of the systems of equations. State which systems have no solution or an infinite number of solutions.
1. x-y+2z=3
-6x+y+3z=7
x+2y-5z=-4

2. x-y-2z=3
x+2