Question

problem 19: (first taught in lesson 16) if y = 5x and z = 4x, find x.

Explanation:

Step1: Set up equation

Since the sum of angles on a straight - line is $180^{\circ}$, we have $x + y+z=180$.

Step2: Substitute $y$ and $z$

Substitute $y = 5x$ and $z = 4x$ into the equation: $x+5x + 4x=180$.

Step3: Combine like - terms

$(1 + 5+4)x=180$, so $10x=180$.

Step4: Solve for $x$

Divide both sides by 10: $x=\frac{180}{10}=20$.

Answer:

$20$