Question

The three angles $(5x+4{)}^{\circ }$, $(x-2{)}^{\circ }$ and $(3x+7{)}^{\circ }$ forms a straight angle. Find the value of $x$.
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Answer 1

Straight angle $={180}^{\circ }$

$\Rightarrow (5x+4{)}^{\circ }+(x-2{)}^{\circ }+(3x+7{)}^{\circ }={180}^{\circ }$.
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$\Rightarrow (5x+x+3x{)}^{\circ }+(4-2+7{)}^{\circ }={180}^{\circ }$.

$\Rightarrow (9x+9{)}^{\circ }={180}^{\circ }$.

$\Rightarrow 9(x+1{)}^{\circ }={180}^{\circ }$.

$\Rightarrow (x+1{)}^{\circ }={20}^{\circ }$.

$\Rightarrow x^{\circ }={20}^{\circ }-1^{\circ }$.

$\Rightarrow x^{\circ }={19}^{\circ }$.

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> $\left[1.5\right]$