Answer
Life expectancy:
chimp 53 years
elephant 77 years
Work Step by Step
Let $x$ be life expectancy for a chimp.
Life expectancy for an elephant is $x+24$.
$x+x+24=130$ $\longrightarrow$combine like terms
$2x+24=130$ $\longrightarrow$addition property
$2x+24-24=130-24$ $\longrightarrow$simplify
$2x=106$ $\longrightarrow$multiplication property
$2x\div2=106\div2$ $\longrightarrow$simplify
$x=53$
$x+24=53+24=77$
