2. Solve each equation by rewriting it in factored form and using the zero prod property. Show your reasoning. a. \( x^{2}+8 x+15=0 \) b. \( x^{2}-8 x+12=5 \) c. \( x^{2}-10 x-11=0 \) d. \( 49-x^{2}=0 \) e. \( (x+4)(x+5)-30=0 \)
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To solve these equations, let's rewrite them in factored form and apply the zero product property. **a. \( x^{2}+8x+15=0 \)** First, we need to factor the quadratic. We look for two numbers that multiply to \(15\) and add to \(8\). Those numbers are \(3\) and \(5\). Thus, we can factor this as: \[(x+3)(x+5)=0\] Using the zero product property, we set each factor equal to zero: \(x+3=0 \Rightarrow x=-3\) \(x+5=0 \Rightarrow x=-5\) So, the solutions are \(x=-3\) and \(x=-5\). **b. \( x^{2}-8x+12=5 \)** First, move \(5\) to the left side: \[x^{2}-8x+7=0\] Next, we factor the quadratic: we need two numbers that multiply to \(7\) and add to \(-8\), which are \(-1\) and \(-7\). So we have: \[(x-1)(x-7)=0\] Setting each factor equal to zero gives us: \(x-1=0 \Rightarrow x=1\) \(x-7=0 \Rightarrow x=7\) Thus, the solutions are \(x=1\) and \(x=7\). **c. \( x^{2}-10x-11=0 \)** To factor this quadratic, we look for two numbers that multiply to \(-11\) and add to \(-10\). The numbers are \(-11\) and \(1\): \[(x-11)(x+1)=0\] Setting each factor to zero results in: \(x-11=0 \Rightarrow x=11\) \(x+1=0 \Rightarrow x=-1\) So the solutions are \(x=11\) and \(x=-1\). **d. \( 49-x^{2}=0 \)** We can rearrange this to \(x^{2}=49\). Next, we can rewrite it in factored form: \[(7-x)(7+x)=0\] Setting each factor to zero gives us: \(7-x=0 \Rightarrow x=7\) \(7+x=0 \Rightarrow x=-7\) Thus, the solutions are \(x=7\) and \(x=-7\). **e. \( (x+4)(x+5)-30=0 \)** First, we set this up as \( (x+4)(x+5)=30 \). To make it simpler, let’s expand it: \[x^2 + 9x + 20 - 30 = 0 \] which simplifies to: \[x^2 + 9x - 10 = 0\] Now, we factor this quadratic. We need numbers that multiply to \(-10\) and add to \(9\), which are \(10\) and \(-1\): \[(x+10)(x-1)=0\] Therefore, setting both factors to zero, we find: \(x+10=0 \Rightarrow x=-10\) \(x-1=0 \Rightarrow x=1\) The solutions are \(x=-10\) and \(x=1\).